Biventricular Versus Right Ventricular Pacing in Heart Failure Patients With Atrioventricular Block (BLOCK HF)

• Sponsor: Medtronic Cardiac Rhythm and Heart Failure (Industry)
• Overall Status: Completed
• CT.gov ID: NCT00267098
• Collaborator: (none)
• Enrollment: 918
• Locations: 54
• Arms: 2
• Duration (Months): 111
• Patients Per Site: 17
• Patients Per Site Per Month: 0.2

Study Details

Study Description

Brief Summary

Heart failure is a progressive disease that decreases the pumping action of the heart. This may cause a backup of fluid in the heart and may result in heart beat changes. When there are changes in the heartbeat, sometimes a pacemaker is used to control the rate and rhythm of the heartbeat. In this trial, the researchers will test if pacing both the left and right lower half of the heart (ventricles) will:

• decrease the number of hospital and clinic visits due to heart failure symptoms

• extend life

• delay heart failure symptoms as compared to those who are paced in only one ventricle (the right ventricle)

Condition or Disease	Intervention/Treatment	Phase
Atrioventricular Block; Heart Diseases	Device: Cardiac Resynchronization Therapy (CRT); Device: Cardiac Resynchronization Therapy (CRT)	N/A

Study Design

• Study Type: Interventional
• Actual Enrollment: 918 participants
• Allocation: Randomized
• Intervention Model: Parallel Assignment
• Masking: Double (Participant, Outcomes Assessor)
• Primary Purpose: Treatment
• Official Title: Biventricular Versus Right Ventricular Pacing in Heart Failure Patients With Atrioventricular Block (BLOCK HF)
• Study Start Date: Dec 1, 2003
• Actual Primary Completion Date: Dec 1, 2012
• Actual Study Completion Date: Mar 1, 2013

Arms and Interventions

Arm	Intervention/Treatment
Experimental: Biventricular pacing	Device: Cardiac Resynchronization Therapy (CRT); Biventricular pacing; Other Names: Medtronic CRT-P Medtronic CRT-D
Active Comparator: Right ventricular pacing	Device: Cardiac Resynchronization Therapy (CRT); Right ventricular pacing; Other Names: Medtronic CRT-P Medtronic CRT-D

Outcome Measures

Primary Outcome Measures

1. Mortality, Heart Failure-related Urgent Care Visits, or Significant Increase in Left Ventricular End Systolic Volume Index (LVESVI) [Participants were followed for the duration of the study, an average of 39.8 months post-randomization.]

   Events include all-cause mortality, heart failure(HF)-related urgent care (a healthcare utilization visit involving intravenous(IV) therapy for heart failure) or significant increase(at least 15%) in LVESVI (a measure of the volume of a patient's left ventricle) from randomization to a later time point. Time from randomization until the subject experienced one of these events served as the outcome measure. LVESVI endpoints occurred primarily at those visits in which LVESVI measurements were required (6, 12, 18, 24 months). Because endpoints such as death or HF urgent care could occur at any time during follow-up, the subject's outcome measure could range from less than 1 month to 105 months (maximum follow-up duration). Primary endpoints and follow-up data occurring after a subject missed a required LVESVI measurement were excluded from the analysis and the table below. The counts reflect the number of subjects meeting each endpoint, and are not necessarily mutually exclusive.

Secondary Outcome Measures

1. All-Cause Mortality [Participants were followed for the duration of the study, an average of 39.8 months post-randomization.]

   The endpoint is the time to death from any cause. The rate of mortality, as measure by the hazard rate, in each randomization arm will be compared. This outcome includes all post-randomization deaths, whereas the reporting of the primary outcome excluded primary endpoints (including deaths) that occurred after the subject had missed a study-required echocardiogram (used to determine if the LVESVI primary endpoint was met).

2. All-Cause Mortality or Heart Failure-related Hospitalization [Participants were followed for the duration of the study, an average of 39.8 months post-randomization.]

   The endpoint will be a subject's time from randomization to either their first heart failure-related hospitalization, or death.

3. All-Cause Mortality or Significant Increase in Left Ventricular End Systolic Volume Index [Participants were followed for the duration of the study, an average of 39.8 months post-randomization.]

   The endpoint will be the time from randomization to either death or a visit (6, 12, 18, 24 month or interim visit) in which the subject undergoes an echocardiogram and the measured left ventricular end systolic volume index (a measure of the size of the subject's left ventricle normalized over their body surface area) is at least 15% greater than the corresponding measured value at randomization. Only LVESVI endpoints/deaths and follow-up data occurring before a subject missed an LVESVI measurement (due to missed visit, echo not performed, etc.) were used in the analysis and included in the table below. The counts reflect the number of subjects meeting each endpoint, and are not mutually exclusive.

4. First Heart Failure Hospitalization [Participants were followed for the duration of the study, an average of 39.8 months post-randomization.]

   The endpoint is the time from randomization to a subject's first heart failure (HF)-related hospitalization. For each randomization arm, the number of subjects who met the endpoint, experiencing at least one heart failure-related hospitalization post-randomization, are reported, as well as the number of randomized subjects who did not experience any HF hospitalizations post-randomization.

5. Days Hospitalized for Heart Failure [Participants were followed for the duration of the study, an average of 39.8 months post-randomization.]

   For each subject the endpoint was the days hospitalized for heart failure per patient year, calculated as the total number of days the subject was hospitalized for heart failure divided by the subject's total follow-up time. Only post-randomization data were used.

6. Change in New York Heart Association Classification [Randomization to 24 Months]

   The endpoint is a subject's change in New York Heart Association Classification (a measure of the degree of heart failure a subject has on a 4 class scale, with NYHA I being the healthiest score and NYHA IV being the sickest score) from randomization to each of four time points: 6 months, 12 months, 18 months, and 24 months post-randomization. The change categories listed will be relative to randomization.

7. Change in Heart Failure Stage [Randomization to 24 Months]

   The endpoint is a subject's change in Heart Failure Stage (a measure of the degree of heart failure a subject has on a 4 stage scale (A, B, C, D), with Class A being the healthiest score and Class D being the sickest score) from randomization to each of four time points: 6 months, 12 months, 18 months, and 24 months.

8. Change in Cardiovascular Medications [Participants were followed for the duration of the study, an average of 39.8 months post-randomization.]

   The endpoints are what classes of drugs (e.g. Beta blockers, Diuretics, Nitrates, etc.) each subject was on at the time of scheduled visits (e.g Randomization, 6 months, 12 months, etc.)

9. Frequency of Adverse Events Post-randomization [Participants were followed for the duration of the study, an average of 39.8 months post-randomization.]

   Adverse events that subjects experienced after they were randomized were compared between arms with regard to several categories such as heart failure (HF)-relatedness, relatedness to the implant procedure, and relatedness to the implanted system, including individual components such as the left ventricular (LV) lead and the CRT-P or CRT-D generator.

10. Cardiovascular-related Healthcare Utilizations [Participants were followed for the duration of the study, an average of 39.8 months post-randomization.]

    Cardiovascular-related healthcare utilizations (HCUs), such as hospitalizations, Emergency Department visits, urgent care visits, and clinic visits that subjects experienced after being randomized were summarized for each randomization arm

11. Change in Quality of Life at 6 Months [Randomization to 6 Months]

    The endpoint will be a subject's change in Quality of Life score from randomization to 6 months. The Quality of Life score at a time point is calculated using the Minnesota Living with Heart Failure Questionnaire, which consists of 21 questions each on a 6 point scale from 0 to 5. The 21 scores are added up and the final score, ranging from 0 (best) to 105 (worst) is the subject's quality of life score. For each subject the measure will be the randomization visit - 6 month difference in QOL score, with positive values denoting a reduction in score and improvement in Quality of Life. Subjects with missing QOL scores at one or both time points were excluded from analysis, and so the number of subjects analyzed for this outcome was a subset of the number of randomized subjects.

12. Change in Quality of Life at 12 Months [Randomization to 12 months]

    The endpoint will be a subject's change in Quality of Life score from randomization to 12 months. The Quality of Life score at a time point is calculated using the Minnesota Living with Heart Failure Questionnaire, which consists of 21 questions each on a 6 point scale from 0 to 5. The 21 scores are added up and the final score, ranging from 0 (best) to 105 (worst) is the subject's quality of life score. For each subject the measure will be the randomization visit - 12 month difference in QOL score, with positive values denoting a reduction in score and improvement in Quality of Life. Subjects with missing QOL scores at one or both time points were excluded from analysis, and so the number of subjects analyzed for this outcome was a subset of the number of randomized subjects.

13. Change in Quality of Life at 18 Months [Randomization to 18 Months]

    The endpoint will be a subject's change in Quality of Life score from randomization to 18 months. The Quality of Life score at a time point is calculated using the Minnesota Living with Heart Failure Questionnaire, which consists of 21 questions each on a 6 point scale from 0 to 5. The 21 scores are added up and the final score, ranging from 0 (best) to 105 (worst) is the subject's quality of life score. For each subject the measure will be the randomization visit - 18 month difference in QOL score, with positive values denoting a reduction in score and improvement in Quality of Life. Subjects with missing QOL scores at one or both time points were excluded from analysis, and so the number of subjects analyzed for this outcome was a subset of the number of randomized subjects.

14. Change in Quality of Life at 24 Months [Randomization to 24 Months]

    The endpoint will be a subject's change in Quality of Life score from randomization to 24 months. The Quality of Life score at a time point is calculated using the Minnesota Living with Heart Failure Questionnaire, which consists of 21 questions each on a 6 point scale from 0 to 5. The 21 scores are added up and the final score, ranging from 0 (best) to 105 (worst) is the subject's quality of life score. For each subject the measure will be the randomization visit - 24 month difference in QOL score, with positive values denoting a reduction in score and improvement in Quality of Life. Subjects with missing QOL scores at one or both time points were excluded from analysis, and so the number of subjects analyzed for this outcome was a subset of the number of randomized subjects.

15. Change in Left Ventricular Ejection Fraction (LVEF) From Randomization to 6 Months [Randomization to 6 Months]

    The endpoint will be a subject's change in LV Ejection Fraction (a measure of the percentage of blood ejected from the left ventricle of the heart with each contraction). A normal range is 55% to 70%. For each subject the measure will be the 6 month - randomization visit difference in LVEF value.

16. Change in Left Ventricular Ejection Fraction (LVEF) From Randomization to 12 Months [Randomization to 12 Months]

    The endpoint will be a subject's change in LV Ejection Fraction (a measure of the percentage of blood ejected from the left ventricle of the heart with each contraction). A normal range is 55% to 70%. For each subject the measure will be the 12 month - randomization visit difference in LVEF value.

17. Change in Left Ventricular Ejection Fraction (LVEF) From Randomization to 18 Months [Randomization to 18 Months]

    The endpoint will be a subject's change in LV Ejection Fraction (a measure of the percentage of blood ejected from the left ventricle of the heart with each contraction). A normal range is 55% to 70%. For each subject the measure will be the 18 month - randomization visit difference in LVEF value.

18. Change in Left Ventricular Ejection Fraction (LVEF) From Randomization to 24 Months [Randomization to 24 Months]

    The endpoint will be a subject's change in LV Ejection Fraction (a measure of the percentage of blood ejected from the left ventricle of the heart with each contraction). A normal range is 55% to 70%. For each subject the measure will be the 24 month - randomization visit difference in LVEF value.

19. Change in Left Ventricular End Systolic Volume Index (LVESVI) From Randomization to 6 Months [Randomization to 6 Months]

    The endpoint will be a subject's change in Left Ventricular End Systolic Volume Index (a measure of the volume of blood in the left ventricle at the end of systole, normalized over body surface area). In other words, a measure of the size of the left ventricle. For each subject the measure is the 6 month - randomization visit difference in LVESVI. Negative values correspond to reductions in LVESVI over time.

20. Change in Left Ventricular End Systolic Volume Index (LVESVI) From Randomization to 12 Months [Randomization to 12 Months]

    The endpoint will be a subject's change in Left Ventricular End Systolic Volume Index (a measure of the volume of blood in the left ventricle at the end of systole, normalized over body surface area). In other words, a measure of the size of the left ventricle. For each subject the measure is the 12 month - randomization visit difference in LVESVI. Negative values correspond to reductions in LVESVI over time.

21. Change in Left Ventricular End Systolic Volume Index (LVESVI) From Randomization to 18 Months [Randomization to 18 Months]

    The endpoint will be a subject's change in Left Ventricular End Systolic Volume Index (a measure of the volume of blood in the left ventricle at the end of systole, normalized over body surface area). In other words, a measure of the size of the left ventricle. For each subject the measure is the 18 month - randomization visit difference in LVESVI. Negative values correspond to reductions in LVESVI over time.

22. Change in Left Ventricular End Systolic Volume Index (LVESVI) From Randomization to 24 Months [Randomization to 24 Months]

    The endpoint will be a subject's change in Left Ventricular End Systolic Volume Index (a measure of the volume of blood in the left ventricle at the end of systole, normalized over body surface area). In other words, a measure of the size of the left ventricle. For each subject the measure is the 24 month - randomization visit difference in LVESVI. Negative values correspond to reductions in LVESVI over time.

23. Change in Left Ventricular End Diastolic Volume Index (LVEDVI) From Randomization to 6 Months [Randomization to 6 Months]

    The endpoint will be a subject's change in Left Ventricular End Diastolic Volume Index (a measure of the volume of blood in the left ventricle at the end of diastole, normalized over body surface area). In other words, a measure of the size of the left ventricle. For each subject the measure is the 6 month - randomization visit difference in LVEDVI. Negative values correspond to reductions in LVEDVI over time.

24. Change in Left Ventricular End Diastolic Volume Index (LVEDVI) From Randomization to 12 Months [Randomization to 12 Months]

    The endpoint will be a subject's change in Left Ventricular End Diastolic Volume Index (a measure of the volume of blood in the left ventricle at the end of diastole, normalized over body surface area). In other words, a measure of the size of the left ventricle. For each subject the measure is the 12 month - randomization visit difference in LVEDVI. Negative values correspond to reductions in LVEDVI over time.

25. Change in Left Ventricular End Diastolic Volume Index (LVEDVI) From Randomization to 18 Months [Randomization to 18 Months]

    The endpoint will be a subject's change in Left Ventricular End Diastolic Volume Index (a measure of the volume of blood in the left ventricle at the end of diastole, normalized over body surface area). In other words, a measure of the size of the left ventricle. For each subject the measure is the 18 month - randomization visit difference in LVEDVI. Negative values correspond to reductions in LVEDVI over time.

26. Change in Left Ventricular End Diastolic Volume Index (LVEDVI) From Randomization to 24 Months [Randomization to 24 Months]

    The endpoint will be a subject's change in Left Ventricular End Diastolic Volume Index (a measure of the volume of blood in the left ventricle at the end of diastole, normalized over body surface area). In other words, a measure of the size of the left ventricle. For each subject the measure is the 24 month - randomization visit difference in LVEDVI. Negative values correspond to reductions in LVEDVI over time.

27. Change in Left Ventricular Mass (LV Mass) From Randomization to 6 Months [Randomization to 6 Months]

    The endpoint will be a subject's change in Left Ventricular Mass ( a measure of the size of the left ventricle) from randomization to 6 months. For each subject the measurement was calculated as 6 month - randomization visit difference in LV mass measurement. Negative values correspond to a reduction in LV mass over time.

28. Change in Left Ventricular Mass (LV Mass) From Randomization to 12 Months [Randomization to 12 Months]

    The endpoint will be a subject's change in Left Ventricular Mass ( a measure of the size of the left ventricle) from randomization to 12 months. For each subject the measurement was calculated as 12 month - randomization visit difference in LV mass measurement. Negative values correspond to a reduction in LV mass over time.

29. Change in Left Ventricular Mass (LV Mass) From Randomization to 18 Months [Randomization to 18 Months]

    The endpoint will be a subject's change in Left Ventricular Mass ( a measure of the size of the left ventricle) from randomization to 18 months. For each subject the measurement was calculated as 18 month - randomization visit difference in LV mass measurement. Negative values correspond to a reduction in LV mass over time.

30. Change in Left Ventricular Mass (LV Mass) From Randomization to 24 Months [Randomization to 24 Months]

    The endpoint will be a subject's change in Left Ventricular Mass ( a measure of the size of the left ventricle) from randomization to 24 months. For each subject the measurement was calculated as 24 month - randomization visit difference in LV mass measurement. Negative values correspond to a reduction in LV mass over time.

31. Change in Left Ventricular End Diastolic Dimension (LVEDD) From Randomization to 6 Months [Randomization to 6 Months]

    The endpoint will be a subject's change in LVEDD (a measure of the dimension of the left ventricle at the end of diastole). For each subject the measure was the 6 month - randomization visit difference in LVEDD value. Negative values correspond to reductions in LVEDD.

32. Change in Left Ventricular End Diastolic Dimension (LVEDD) From Randomization to 12 Months [Randomization to 12 Months]

    The endpoint will be a subject's change in LVEDD (a measure of the dimension of the left ventricle at the end of diastole). For each subject the measure was the 12 month - randomization visit difference in LVEDD value. Negative values correspond to reductions in LVEDD.

33. Change in Left Ventricular End Diastolic Dimension (LVEDD) From Randomization to 18 Months [Randomization to 18 Months]

    The endpoint will be a subject's change in LVEDD (a measure of the dimension of the left ventricle at the end of diastole). For each subject the measure was the 18 month - randomization visit difference in LVEDD value. Negative values correspond to reductions in LVEDD.

34. Change in Left Ventricular End Diastolic Dimension (LVEDD) From Randomization to 24 Months [Randomization to 24 Months]

    The endpoint will be a subject's change in LVEDD (a measure of the dimension of the left ventricle at the end of diastole). For each subject the measure was the 24 month - randomization visit difference in LVEDD value. Negative values correspond to reductions in LVEDD.

35. Change in Left Ventricular End Systolic Dimension (LVESD) From Randomization to 6 Months [Randomization to 6 Months]

    The endpoint will be a subject's change in LVESD (a measure of the dimension of the left ventricle at the end of systole). For each subject the measure was the 6 month - randomization visit difference in LVESD value. Negative values correspond to reductions in LVESD.

36. Change in Left Ventricular End Systolic Dimension (LVESD) From Randomization to 12 Months [Randomization to 12 Months]

    The endpoint will be a subject's change in LVESD (a measure of the dimension of the left ventricle at the end of systole). For each subject the measure was the 12 month - randomization visit difference in LVESD value. Negative values correspond to reductions in LVESD.

37. Change in Left Ventricular End Systolic Dimension (LVESD) From Randomization to 18 Months [Randomization to 18 Months]

    The endpoint will be a subject's change in LVESD (a measure of the dimension of the left ventricle at the end of systole). For each subject the measure was the 18 month - randomization visit difference in LVESD value. Negative values correspond to reductions in LVESD.

38. Change in Left Ventricular End Systolic Dimension (LVESD) From Randomization to 24 Months [Randomization to 24 Months]

    The endpoint will be a subject's change in LVESD (a measure of the dimension of the left ventricle at the end of systole). For each subject the measure was the 24 month - randomization visit difference in LVESD value. Negative values correspond to reductions in LVESD.

39. Change in Mitral Regurgitation From Randomization to 6 Months [Randomization to 6 Months]

    The endpoint will be a subject's change in mitral regurgitation (a measure of how much blood flows backwards into the heart due to the mitral valve not closing properly). The measure for each subject will be the 6 month - randomization visit difference in mitral regurgitation. Negative values reflect reductions in mitral regurgitation over time.

40. Change in Mitral Regurgitation From Randomization to 12 Months [Randomization to 12 Months]

    The endpoint will be a subject's change in mitral regurgitation (a measure of how much blood flows backwards into the heart due to the mitral valve not closing properly). The measure for each subject will be the 12 month - randomization visit difference in mitral regurgitation. Negative values reflect reductions in mitral regurgitation over time.

41. Change in Mitral Regurgitation From Randomization to 18 Months [Randomization to 18 Months]

    The endpoint will be a subject's change in mitral regurgitation (a measure of how much blood flows backwards into the heart due to the mitral valve not closing properly). The measure for each subject will be the 18 month - randomization visit difference in mitral regurgitation. Negative values reflect reductions in mitral regurgitation over time.

42. Change in Mitral Regurgitation From Randomization to 24 Months [Randomization to 24 Months]

    The endpoint will be a subject's change in mitral regurgitation (a measure of how much blood flows backwards into the heart due to the mitral valve not closing properly). The measure for each subject will be the 24 month - randomization visit difference in mitral regurgitation. Negative values reflect reductions in mitral regurgitation over time.

43. Change in Cardiac Index From Randomization to 6 Months [Randomization to 6 Months]

    The endpoint will be a subject's change in cardiac index (a measure of how much blood the left ventricle ejects in one minute, normalized over body surface area) from randomization to 6 months. The measure for each subject will be the 6 month - randomization visit value.

44. Change in Cardiac Index From Randomization to 12 Months [Randomization to 12 Months]

    The endpoint will be a subject's change in cardiac index (a measure of how much blood the left ventricle ejects in one minute, normalized over body surface area) from randomization to 12 months. The measure for each subject will be the 12 month - randomization visit value.

45. Change in Cardiac Index From Randomization to 18 Months [Randomization to 18 Months]

    The endpoint will be a subject's change in cardiac index (a measure of how much blood the left ventricle ejects in one minute, normalized over body surface area) from randomization to 18 months. The measure for each subject will be the 18 month - randomization visit value.

46. Change in Cardiac Index From Randomization to 24 Months [Randomization to 24 Months]

    The endpoint will be a subject's change in cardiac index (a measure of how much blood the left ventricle ejects in one minute, normalized over body surface area) from randomization to 24 months. The measure for each subject will be the 24 month - randomization visit value.

47. Change in Interventricular Mechanical Delay (IVMD) From Randomization to 6 Months [Randomization to 6 Months]

    The endpoint will be a subject's change in interventricular mechanical delay (a measure of dyssynchrony between ventricles, measured in ms) from randomization to the 6 month visit. The measure will be the 6 month - randomization visit difference in IVMD.

48. Change in Interventricular Mechanical Delay (IVMD) From Randomization to 12 Months [Randomization to 12 Months]

    The endpoint will be a subject's change in interventricular mechanical delay (a measure of dyssynchrony between ventricles, measured in ms) from randomization to the 12 month visit. The measure will be the 12 month - randomization visit difference in IVMD.

49. Change in Interventricular Mechanical Delay (IVMD) From Randomization to 18 Months [Randomization to 18 Months]

    The endpoint will be a subject's change in interventricular mechanical delay (a measure of dyssynchrony between ventricles, measured in ms) from randomization to the 18 month visit. The measure will be the 18 month - randomization visit difference in IVMD.

50. Change in Interventricular Mechanical Delay (IVMD) From Randomization to 24 Months [Randomization to 24 Months]

    The endpoint will be a subject's change in interventricular mechanical delay (a measure of dyssynchrony between ventricles, measured in ms) from randomization to the 24 month visit. The measure will be the 24 month - randomization visit difference in IVMD.

51. Change in E Wave/A Wave Ratio (E:A Ratio) From Randomization to 6 Months [Randomization to 6 Months]

    The endpoint will be a subject's change in E:A ratio (a measure of diastolic function) from randomization to 6 months. The measure for each subject will be the 6 month - randomization visit difference in E:A ratio. Typical values for the E:A ratio at a single time point are 1.04 in men and 1.03 in women.

52. Change in E Wave/A Wave Ratio (E:A Ratio) From Randomization to 12 Months [Randomization to 12 Months]

    The endpoint will be a subject's change in E:A ratio (a measure of diastolic function) from randomization to 12 months. The measure for each subject will be the 12 month - randomization visit difference in E:A ratio. Typical values for the E:A ratio at a single time point are 1.04 in men and 1.03 in women.

53. Change in E Wave/A Wave Ratio (E:A Ratio) From Randomization to 18 Months [Randomization to 18 Months]

    The endpoint will be a subject's change in E:A ratio (a measure of diastolic function) from randomization to 18 months. The measure for each subject will be the 18 month - randomization visit difference in E:A ratio. Typical values for the E:A ratio at a single time point are 1.04 in men and 1.03 in women.

54. Change in E Wave/A Wave Ratio (E:A Ratio) From Randomization to 24 Months [Randomization to 24 Months]

    The endpoint will be a subject's change in E:A ratio (a measure of diastolic function) from randomization to 24 months. The measure for each subject will be the 24 month - randomization visit difference in E:A ratio. Typical values for the E:A ratio at a single time point are 1.04 in men and 1.03 in women.

55. Clinical Composite Score at 6 Months [Randomization to 6 Months]

    The endpoint will be a subject's Clinical Composite Score at 6 months. The Clinical Composite Score is a 3 point score (Worsened, Unchanged, and Improved) based on a number of factors including: whether the subject has died, whether the subject has experienced a heart failure-related hospitalization, whether the subject has discontinued their therapy due to worsening heart failure, whether their New York Heart Association classification has improved or worsened since randomization, and whether they feel moderately or markedly better since randomization.

56. Clinical Composite Score at 12 Months [Randomization to 12 Months]

    The endpoint will be a subject's Clinical Composite Score at 12 months. The Clinical Composite Score is a 3 point score (Worsened, Unchanged, and Improved) based on a number of factors including: whether the subject has died, whether the subject has experienced a heart failure-related hospitalization, whether the subject has discontinued their therapy due to worsening heart failure, whether their New York Heart Association classification has improved or worsened since randomization, and whether they feel moderately or markedly better since randomization.

57. Clinical Composite Score at 18 Months [Randomization to 18 Months]

    The endpoint will be a subject's Clinical Composite Score at 18 months. The Clinical Composite Score is a 3 point score (Worsened, Unchanged, and Improved) based on a number of factors including: whether the subject has died, whether the subject has experienced a heart failure-related hospitalization, whether the subject has discontinued their therapy due to worsening heart failure, whether their New York Heart Association classification has improved or worsened since randomization, and whether they feel moderately or markedly better since randomization.

58. Clinical Composite Score at 24 Months [Randomization to 24 Months]

    The endpoint will be a subject's Clinical Composite Score at 24 months. The Clinical Composite Score is a 3 point score (Worsened, Unchanged, and Improved) based on a number of factors including: whether the subject has died, whether the subject has experienced a heart failure-related hospitalization, whether the subject has discontinued their therapy due to worsening heart failure, whether their New York Heart Association classification has improved or worsened since randomization, and whether they feel moderately or markedly better since randomization.

59. CRT-P and CRT-D System Implant Success [Initial Implant Procedure]

    The endpoint will be whether each subject who underwent an implant attempt of a Cardiac Resynchronization Therapy device, be it a pacing only device (CRT-P) or a pacing device with defibrillation capability (CRT-D), had a successful procedure (i.e. the generator, left ventricular lead, and right ventricular lead were successfully implanted). Only one implant attempt was allowed.

60. Incidence of Ventricular Tachyarrhythmias [Participants were followed for the duration of the study, an average of 37.9 months post-randomization among CRT-D subjects.]

    Among subjects implanted with a Cardiac Resynchronization Therapy with Defibrillation device (CRT-D) and randomized, the endpoint was the time from randomization until the subject experienced a ventricular tachyarrhythmia. For each randomization arm, the number of CRT-D subjects who experienced at least one ventricular tachyarrhythmia post-randomization is reported, as well as the number of CRT-D subjects who did not experience one or more ventricular tachyarrhythmias post-randomization.

Eligibility Criteria

Criteria

• Ages Eligible for Study: 18 Years and Older
• Sexes Eligible for Study: All
• Accepts Healthy Volunteers: No

Inclusion Criteria:

• Subject has standard class I or class IIa indication for pacemaker implantation in accordance with ACC/AHA/HRS guidelines

• Subjects diagnosed with atrioventricular (AV) block. An AV block is a disturbance when the heart's natural pacemaker sends a message from the atrium (top part of heart) to the ventricle (bottom part of heart) and the message is partially or totally blocked

• Subject is receiving first time implant

• Subjects with heart failure but no symptoms of it (New York Heart Association [NYHA] Class I), or subjects with mild heart failure that only sometimes interferes with their daily activities (NYHA Class II), or subjects with heart failure that severely limits daily activities (NYHA Class III)

• Subjects with documented reduced heart pumping function (left ventricular ejection fraction ≤ 50%) within past 90 days

• Subject is at least 18 years old

• Subject or authorized legal guardian or representative has signed and dated the Informed Consent

• Subject is able to receive a pectoral implant

• Subject is expected to remain available for follow-up visits at the study center

• Subject is willing and able to comply with the protocol

Exclusion Criteria:

• Subject has ever had a previous or has an existing device implant

• Subjects with some forms of chest pain or myocardial infarction (heart attack) within the past 30 days

• Subjects with coronary bypass within the past 30 days

• Subjects with stent within the past 30 days

• Subjects with valve repair or replacement within the past 6 months or is indicated for repair or replacement

• Subjects with a mechanical right heart valve

• Subject is indicated for a biventricular pacing device (CRT-P or CRT-D devices)

• Subject is enrolled in a concurrent study which may confound the results of this study (co-enrollment in any concurrent clinical study requires approval of the study manager)

• Subject is pregnant, or of child bearing potential and not on a reliable form of birth control

• Subjects with a previous heart transplant

• Subjects has been classified as NHYA Functional Class IV within prior 90 days (subjects with severe heart failure and should always be resting)

• Subject, legal guardian or authorized representative is unable or unwilling to cooperate or give written informed consent

Contacts and Locations

Locations

	Site	City	State	Country	Postal Code
1		Anchorage	Alaska	United States
2		Peoria	Arizona	United States
3		Little Rock	Arkansas	United States
4		Glendale	California	United States
5		Long Beach	California	United States
6		Colorado Springs	Colorado	United States
7		Hollywood	Florida	United States
8		Jacksonville	Florida	United States
9		Pensacola	Florida	United States
10		Tampa	Florida	United States
11		Park Ridge	Illinois	United States
12		Rockford	Illinois	United States
13		Davenport	Iowa	United States
14		Lexington	Kentucky	United States
15		Lacombe	Louisiana	United States
16		Boston	Massachusetts	United States
17		Grand Rapids	Michigan	United States
18		Petoskey	Michigan	United States
19		Ypsilanti	Michigan	United States
20		Minneapolis	Minnesota	United States
21		St. Louis Park	Minnesota	United States
22		Kansas City	Missouri	United States
23		St. Louis	Missouri	United States
24		Lincoln	Nebraska	United States
25		Camden	New Jersey	United States
26		Hackensack	New Jersey	United States
27		Ridgewood	New Jersey	United States
28		Bay Shore	New York	United States
29		Rochester	New York	United States
30		Syracuse	New York	United States
31		West Islip	New York	United States
32		Cincinnati	Ohio	United States
33		Cleveland	Ohio	United States
34		Oklahoma City	Oklahoma	United States
35		Tulsa	Oklahoma	United States
36		Danville	Pennsylvania	United States
37		Doylestown	Pennsylvania	United States
38		Ephrata	Pennsylvania	United States
39		Lancaster	Pennsylvania	United States
40		Philadelphia	Pennsylvania	United States
41		Wynnewood	Pennsylvania	United States
42		Wyomissing	Pennsylvania	United States
43		Providence	Rhode Island	United States
44		Kingsport	Tennessee	United States
45		Dallas	Texas	United States
46		Fort Worth	Texas	United States
47		Fairfax	Virginia	United States
48		Norfolk	Virginia	United States
49		Spokane	Washington	United States
50		Morgantown	West Virginia	United States
51		Milwaukee	Wisconsin	United States
52		Kitchener	Ontario	Canada
53		Toronto	Ontario	Canada
54		Montreal	Quebec	Canada

Sponsors and Collaborators

• Medtronic Cardiac Rhythm and Heart Failure

Investigators

• Principal Investigator: Anne B. Curtis, MD, FHRS, FACC, University at Buffalo, NY

Study Documents (Full-Text)

None provided.

More Information

Publications

None provided.

• Responsible Party: Medtronic Cardiac Rhythm and Heart Failure
• ClinicalTrials.gov Identifier: NCT00267098
• Other Study ID Numbers: 215
• First Posted: Dec 20, 2005
• Last Update Posted: Mar 26, 2014
• Last Verified: Feb 1, 2014

• Keywords provided by Medtronic Cardiac Rhythm and Heart Failure: Atrioventricular block; Cardiac Resynchronization Therapy; Pacemaker; Defibrillator; NYHA Class I, II or III Heart failure
• Additional relevant MeSH terms: Heart Failure; Heart Diseases; Atrioventricular Block

Study Results

Participant Flow

Arm/Group Title	No Implant Attempt	Unsuccessful Implants	CRT-P: Biventricular Pacing Arm	CRT-P: Right Ventricular Pacing Arm	CRT-P: Not Randomized	CRT-D: Biventricular Pacing Arm	CRT-D: Right Ventricular Pacing Arm	CRT-D: Not Randomized
Arm/Group Description	Subjects who did not undergo an implant attempt of a CRT-P or CRT-D device and were not randomized	Subjects who underwent an implant attempt of a CRT-P or CRT-D device but were not successfully implanted	Subjects who were implanted with a CRT-P device and randomized to receive biventricular pacing	Subjects who were implanted with a CRT-P device and randomized to receive right ventricular pacing	Subjects successfully implanted with a CRT-P device who were not randomized	Subjects implanted with a CRT-D device and randomized to receive biventricular pacing	Subjects implanted with a CRT-D device and randomized to receive right ventricular pacing.	Subjects successfully implanted with a CRT-D device who were not randomized
Period Title: Overall Study
STARTED	109	51	243	241	47	106	101	20
COMPLETED	0	0	149	135	10	66	55	5
NOT COMPLETED	109	51	94	106	37	40	46	15

Baseline Characteristics

Arm/Group Title	No Implant Attempt	Unsuccessful Implants	CRT-P: Biventricular Pacing Arm	CRT-P: Right Ventricular Pacing Arm	CRT-P: Not Randomized	CRT-D: Biventricular Pacing Arm	CRT-D: Right Ventricular Pacing Arm	CRT-D: Not Randomized	Total
Arm/Group Description	Subjects who did not undergo an implant attempt of a CRT-P or CRT-D device and were not randomized	Subjects who underwent an implant attempt of a CRT-P or CRT-D device but were not successfully implanted	Subjects who were implanted with a CRT-P device and randomized to receive biventricular pacing	Subjects who were implanted with a CRT-P device and randomized to receive right ventricular pacing	Subjects successfully implanted with a CRT-P device who were not randomized	Subjects implanted with a CRT-D device and randomized to receive biventricular pacing	Subjects implanted with a CRT-D device and randomized to receive right ventricular pacing.	Subjects successfully implanted with a CRT-D device who were not randomized	Total of all reporting groups
Overall Participants	109	51	243	241	47	106	101	20	918
Age (years) [Mean (Standard Deviation) ]
Mean (Standard Deviation) [years]	70.2 (12.6)	71.1 (11.2)	74.4 (10.2)	73.8 (10.8)	79.3 (7.6)	72.0 (9.3)	71.0 (10.0)	74.0 (9.1)	73.2 (10.6)
Sex: Female, Male (Count of Participants)
Female	29 26.6%	14 27.5%	62 25.5%	73 30.3%	18 38.3%	19 17.9%	20 19.8%	4 20%	239 26%
Male	80 73.4%	37 72.5%	181 74.5%	168 69.7%	29 61.7%	87 82.1%	81 80.2%	16 80%	679 74%
Race/Ethnicity, Customized (participants) [Number]
Subject did not offer ethnicity	6 5.5%	2 3.9%	6 2.5%	5 2.1%	1 2.1%	4 3.8%	3 3%	0 0%	27 2.9%
African American	10 9.2%	3 5.9%	8 3.3%	10 4.1%	0 0%	4 3.8%	4 4%	1 5%	40 4.4%
Asian	0 0%	0 0%	0 0%	0 0%	1 2.1%	0 0%	0 0%	0 0%	1 0.1%
Caucasian	91 83.5%	45 88.2%	225 92.6%	224 92.9%	43 91.5%	96 90.6%	90 89.1%	18 90%	832 90.6%
Hispanic	1 0.9%	0 0%	3 1.2%	1 0.4%	2 4.3%	2 1.9%	2 2%	1 5%	12 1.3%
Native American	0 0%	0 0%	0 0%	1 0.4%	0 0%	0 0%	0 0%	0 0%	1 0.1%
Other	1 0.9%	1 2%	1 0.4%	0 0%	0 0%	0 0%	2 2%	0 0%	5 0.5%
Region of Enrollment (participants) [Number]
United States	109 100%	46 90.2%	232 95.5%	231 95.9%	47 100%	104 98.1%	98 97%	19 95%	886 96.5%
Canada	0 0%	5 9.8%	11 4.5%	10 4.1%	0 0%	2 1.9%	3 3%	1 5%	32 3.5%

Outcome Measures

1. Primary Outcome

Title	Mortality, Heart Failure-related Urgent Care Visits, or Significant Increase in Left Ventricular End Systolic Volume Index (LVESVI)
Description	Events include all-cause mortality, heart failure(HF)-related urgent care (a healthcare utilization visit involving intravenous(IV) therapy for heart failure) or significant increase(at least 15%) in LVESVI (a measure of the volume of a patient's left ventricle) from randomization to a later time point. Time from randomization until the subject experienced one of these events served as the outcome measure. LVESVI endpoints occurred primarily at those visits in which LVESVI measurements were required (6, 12, 18, 24 months). Because endpoints such as death or HF urgent care could occur at any time during follow-up, the subject's outcome measure could range from less than 1 month to 105 months (maximum follow-up duration). Primary endpoints and follow-up data occurring after a subject missed a required LVESVI measurement were excluded from the analysis and the table below. The counts reflect the number of subjects meeting each endpoint, and are not necessarily mutually exclusive.
Time Frame	Participants were followed for the duration of the study, an average of 39.8 months post-randomization.

Outcome Measure Data

Analysis Population Description

Only randomized subjects in both device groups were included in the analysis of this endpoint, as the analysis was restricted to post-randomization data. Subjects in the "No Implant Attempt", "Unsuccessful Implants", "CRT-P: Not Randomized", and "CRT-D: Not Randomized" subgroups were excluded.

Arm/Group Title	Biventricular Pacing Arm	Right Ventricular Pacing Arm
Arm/Group Description	Subjects randomized to receive biventricular pacing	Subjects randomized to receive right ventricular pacing.
Measure Participants	349	342
Subjects Experiencing a Primary Endpoint	160 146.8%	191 374.5%
Subjects with an LVESVI Primary Endpoint	93 85.3%	136 266.7%
Subjects with an HF Urgent Care Primary Endpoint	70 64.2%	94 184.3%
Subjects who died	55 50.5%	66 129.4%

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Biventricular Pacing Arm, Right Ventricular Pacing Arm
	Comments	The null hypothesis is that patients with AV block, ejection fractions of at most 50%, and NYHA classifications of I, II, or III who receive biventricular pacing have the same rate of mortality, a heart failure urgent care visit, or significant increase in LVESVI as corresponding patients who receive right ventricular pacing. This was tested against the hypothesis that patients with BiV pacing have a lower rate of this composite endpoint than patients with right ventricular pacing.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value	0.9990
	Comments	BLOCK HF is a Bayesian study;a p-value was not used. Instead, a posterior probability,representing the probability that patients with BiV pacing have lower risk of events than those with RV pacing, was calculated. A probability ≥0.95 was significant.
	Method	Posterior Distribution for HR
	Comments	The posterior distribution is the set of values the BiV to RV hazard ratio can take, and its likelihood of taking such values.
Method of Estimation	Estimation Parameter	Hazard Ratio (HR)
	Estimated Value	0.729
	Confidence Interval	(2-Sided) 95%; 0.592 to 0.889
	Parameter Dispersion	Type: Value:
	Estimation Comments	The hazard ratio corresponds to the time until death, a HF urgent care event or visit in which the LVESVI endpoint was met. Data beyond missed LVESVI measurements were excluded. A 95% credible interval was used instead of a 95% confidence interval.

2. Secondary Outcome

Title	All-Cause Mortality
Description	The endpoint is the time to death from any cause. The rate of mortality, as measure by the hazard rate, in each randomization arm will be compared. This outcome includes all post-randomization deaths, whereas the reporting of the primary outcome excluded primary endpoints (including deaths) that occurred after the subject had missed a study-required echocardiogram (used to determine if the LVESVI primary endpoint was met).
Time Frame	Participants were followed for the duration of the study, an average of 39.8 months post-randomization.

Outcome Measure Data

Analysis Population Description

Only randomized subjects in both device groups were included in the analysis of this endpoint, as the analysis was restricted to post-randomization data. Subjects in the "No Implant Attempt", "Unsuccessful Implants", "CRT-P: Not Randomized", and "CRT-D: Not Randomized" subgroups were excluded.

Arm/Group Title	Biventricular Pacing Arm	Right Ventricular Pacing Arm
Arm/Group Description	Subjects randomized to receive biventricular pacing	Subjects randomized to receive right ventricular pacing.
Measure Participants	349	342
Subjects who died	80 73.4%	94 184.3%
Subjects who did not die	269 246.8%	248 486.3%

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Biventricular Pacing Arm, Right Ventricular Pacing Arm
	Comments	The null hypothesis is that patients with AV block, ejection fractions of at most 50%, and NYHA classifications of I, II, or III who receive biventricular pacing have the same rate of mortality as corresponding patients who receive right ventricular pacing.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value	0.865
	Comments	BLOCK HF is a Bayesian study; thus p-values were not used. Instead, posterior probabilities, representing the probability that subjects with biventricular pacing have better outcomes, were calculated. A probability ≥ 0.95 was significant.
	Method	Posterior Distribution for HR
	Comments	The posterior distribution is the set of values the BiV to RV hazard ratio for death can take, and its likelihood of taking such values.
Method of Estimation	Estimation Parameter	Hazard Ratio (HR)
	Estimated Value	0.843
	Confidence Interval	(2-Sided) 95%; 0.632 to 1.142
	Parameter Dispersion	Type: Value:
	Estimation Comments	Because BLOCK HF was a Bayesian study, a 95% credible interval was used in lieu of a 95% confidence interval. This interval reflects the set of values the Hazard Ratio can take with 95% posterior probability.

3. Secondary Outcome

Title	All-Cause Mortality or Heart Failure-related Hospitalization
Description	The endpoint will be a subject's time from randomization to either their first heart failure-related hospitalization, or death.
Time Frame	Participants were followed for the duration of the study, an average of 39.8 months post-randomization.

Outcome Measure Data

Analysis Population Description

Only randomized subjects in both device groups were included in the analysis of this endpoint, as the analysis was restricted to post-randomization data. Subjects in the "No Implant Attempt", "Unsuccessful Implants", "CRT-P: Not Randomized", and "CRT-D: Not Randomized" subgroups were excluded.

Arm/Group Title	Biventricular Pacing Arm	Right Ventricular Pacing Arm
Arm/Group Description	Subjects randomized to receive biventricular pacing	Subjects randomized to receive right ventricular pacing.
Measure Participants	349	342
Subjects who died or underwent HF hospitalization	121 111%	135 264.7%
Subjects who died	80 73.4%	94 184.3%
Subjects who underwent HF hospitalization	79 72.5%	92 180.4%

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Biventricular Pacing Arm, Right Ventricular Pacing Arm
	Comments	The null hypothesis is that patients with AV block, ejection fractions of at most 50%, and NYHA classifications of I, II, or III who receive biventricular pacing have the same rate of mortality or heart failure(HF)-related hospitalization as corresponding patients who receive right ventricular pacing. This was tested against the hypothesis that patients with biventricular pacing have a lower rate of death or first HF hospitalization than patients with right ventricular pacing.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value	0.9785
	Comments	BLOCK HF is a Bayesian study; a p-value was not used. Instead, a posterior probability, representing the probability that patients with BiV pacing have better outcomes than those with RV pacing, was calculated. A probability ≥0.95 was significant.
	Method	Posterior Distribution for HR
	Comments	The posterior distribution is the set of values the BiV to RV hazard ratio can take, and its likelihood of taking such values.
Method of Estimation	Estimation Parameter	Hazard Ratio (HR)
	Estimated Value	0.781
	Confidence Interval	(2-Sided) 95%; 0.615 to 0.991
	Parameter Dispersion	Type: Value:
	Estimation Comments	Because BLOCK HF was a Bayesian study, a 95% credible interval was used in lieu of a 95% confidence interval. This interval reflects the set of values the Hazard Ratio can take with 95% posterior probability.

4. Secondary Outcome

Title	All-Cause Mortality or Significant Increase in Left Ventricular End Systolic Volume Index
Description	The endpoint will be the time from randomization to either death or a visit (6, 12, 18, 24 month or interim visit) in which the subject undergoes an echocardiogram and the measured left ventricular end systolic volume index (a measure of the size of the subject's left ventricle normalized over their body surface area) is at least 15% greater than the corresponding measured value at randomization. Only LVESVI endpoints/deaths and follow-up data occurring before a subject missed an LVESVI measurement (due to missed visit, echo not performed, etc.) were used in the analysis and included in the table below. The counts reflect the number of subjects meeting each endpoint, and are not mutually exclusive.
Time Frame	Participants were followed for the duration of the study, an average of 39.8 months post-randomization.

Outcome Measure Data

Analysis Population Description

Only randomized subjects in both device groups were included in the analysis of this endpoint, as the analysis was restricted to post-randomization data. Subjects in the "No Implant Attempt", "Unsuccessful Implants", "CRT-P: Not Randomized", and "CRT-D: Not Randomized" subgroups were excluded.

Arm/Group Title	Biventricular Pacing Arm	Right Ventricular Pacing Arm
Arm/Group Description	Subjects randomized to receive biventricular pacing	Subjects randomized to receive right ventricular pacing.
Measure Participants	349	342
Subjects who died or experienced LVESVI event	131 120.2%	171 335.3%
Subjects who died	55 50.5%	66 129.4%
Subjects who experienced LVESVI event	93 85.3%	136 266.7%

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Biventricular Pacing Arm, Right Ventricular Pacing Arm
	Comments	The null hypothesis is that patients with AV block, ejection fractions of at most 50%, and NYHA classifications of I, II, or II who receive biventricular pacing have the same rate of mortality or significant increase in LVESVI as corresponding patients who receive right ventricular pacing. This was tested against the hypothesis that patients with biventricular pacing have a lower rate of death or significant increase in LVESVI than patients with right ventricular pacing.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value	0.9886
	Comments	BLOCK HF is a Bayesian study; a p-value was not used. Instead, a posterior probability, representing the probability that patients with BiV pacing have better outcomes than those with RV pacing, was calculated. A probability ≥0.95 was significant.
	Method	Posterior Distribution for HR
	Comments	The posterior distribution is the set of values the BiV to RV hazard ratio can take, and its likelihood of taking such values.
Method of Estimation	Estimation Parameter	Hazard Ratio (HR)
	Estimated Value	0.695
	Confidence Interval	(2-Sided) 95%; 0.558 to 0.866
	Parameter Dispersion	Type: Value:
	Estimation Comments	The hazard ratio corresponds to the time from randomization to death or a visit in which LVESVI endpoint was met. Data beyond missed LVESVI measurements were excluded. A 95% credible interval was used instead of a 95% confidence interval.

5. Secondary Outcome

Title	First Heart Failure Hospitalization
Description	The endpoint is the time from randomization to a subject's first heart failure (HF)-related hospitalization. For each randomization arm, the number of subjects who met the endpoint, experiencing at least one heart failure-related hospitalization post-randomization, are reported, as well as the number of randomized subjects who did not experience any HF hospitalizations post-randomization.
Time Frame	Participants were followed for the duration of the study, an average of 39.8 months post-randomization.

Outcome Measure Data

Analysis Population Description

Only randomized subjects in both device groups were included in the analysis of this endpoint, as the analysis was restricted to post-randomization data. Subjects in the "No Implant Attempt", "Unsuccessful Implants", "CRT-P: Not Randomized", and "CRT-D: Not Randomized" subgroups were excluded.

Arm/Group Title	Biventricular Pacing Arm	Right Ventricular Pacing Arm
Arm/Group Description	Subjects randomized to receive biventricular pacing	Subjects randomized to receive right ventricular pacing.
Measure Participants	349	342
Subjects experiencing a HF hospitalization	79 72.5%	92 180.4%
Subjects not experiencing a HF hospitalization	270 247.7%	250 490.2%

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Biventricular Pacing Arm, Right Ventricular Pacing Arm
	Comments	The null hypothesis is that patients with AV block, ejection fractions of at most 50%, and NYHA classifications of I, II, or III who receive biventricular pacing have the same rate of first heart failure(HF)-related hospitalization as corresponding patients who receive right ventricular pacing. This was tested against the hypothesis that patients with biventricular pacing have a lower rate of first HF hospitalization than patients with right ventricular pacing.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value	0.9904
	Comments	BLOCK HF is a Bayesian study; a p-value was not used. Instead, a posterior probability, representing the probability that patients with BiV pacing have better outcomes than those with RV pacing, was calculated. A probability ≥0.95 was significant.
	Method	Posterior Distribution for HR
	Comments	The posterior distribution is the set of values the BiV to RV hazard ratio can take, and its likelihood of taking such values.
Method of Estimation	Estimation Parameter	Hazard Ratio (HR)
	Estimated Value	0.704
	Confidence Interval	(2-Sided) 95%; 0.522 to 0.947
	Parameter Dispersion	Type: Value:
	Estimation Comments	Because BLOCK HF was a Bayesian study, a 95% credible interval was used in lieu of a 95% confidence interval. This interval reflects the set of values the Hazard Ratio can take with 95% posterior probability.

6. Secondary Outcome

Title	Days Hospitalized for Heart Failure
Description	For each subject the endpoint was the days hospitalized for heart failure per patient year, calculated as the total number of days the subject was hospitalized for heart failure divided by the subject's total follow-up time. Only post-randomization data were used.
Time Frame	Participants were followed for the duration of the study, an average of 39.8 months post-randomization.

Outcome Measure Data

Analysis Population Description

Only randomized subjects in both device groups were included in the analysis of this endpoint, as the analysis was restricted to post-randomization data. Subjects in the "No Implant Attempt", "Unsuccessful Implants", "CRT-P: Not Randomized", and "CRT-D: Not Randomized" subgroups were excluded.

Arm/Group Title	Biventricular Pacing Arm	Right Ventricular Pacing Arm
Arm/Group Description	Subjects randomized to receive biventricular pacing	Subjects randomized to receive right ventricular pacing.
Measure Participants	349	342
Mean (Standard Deviation) [Days hospitalized per patient year]	1.89 (9.52)	2.63 (16.08)

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Biventricular Pacing Arm, Right Ventricular Pacing Arm
	Comments	The null hypothesis is that patients with AV block, ejection fractions of at most 50%, and NYHA classifications of I, II, or III who receive biventricular pacing have the same rate of days hospitalized for heart failure per year as corresponding patients who receive right ventricular pacing. This was tested against the hypothesis that patients with biventricular pacing have a lower rate of days hospitalized for HF than patients with right ventricular pacing.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value	0.637
	Comments	BLOCK HF is a Bayesian study; a p-value was not used. Instead, a posterior probability, representing the probability that patients with BiV pacing have better outcomes than those with RV pacing, was calculated. A probability ≥0.95 was significant.
	Method	Difference in Average Ranks
	Comments	The subjects' individual rates of days hospitalized for HF were ranked, with lower ranks corresponding to fewer days hospitalized for HF.
Method of Estimation	Estimation Parameter	BiV - RV Difference in Average Rank
	Estimated Value	-1.8
	Confidence Interval	() %; to
	Parameter Dispersion	Type: Value:
	Estimation Comments	The posterior probability that the BiV - RV difference in average ranks was below 0 (denoting that the BiV arm had lower ranks than the RV arm, on average) was calculated.

7. Secondary Outcome

Title	Change in New York Heart Association Classification
Description	The endpoint is a subject's change in New York Heart Association Classification (a measure of the degree of heart failure a subject has on a 4 class scale, with NYHA I being the healthiest score and NYHA IV being the sickest score) from randomization to each of four time points: 6 months, 12 months, 18 months, and 24 months post-randomization. The change categories listed will be relative to randomization.
Time Frame	Randomization to 24 Months

Outcome Measure Data

Analysis Population Description

For each time point(e.g. 6 months), only subjects with NYHA assessed at both randomization and that time point were included in the analysis. Those who could not be analyzed at a time point(for reasons such as death, exit,missed visit,or NYHA not assessed at visit) are listed under the "Comparative data not available" category for that time point.

Arm/Group Title	Biventricular Pacing Arm	Right Ventricular Pacing Arm
Arm/Group Description	Subjects randomized to receive biventricular pacing	Subjects randomized to receive right ventricular pacing.
Measure Participants	349	342
6 Months: Improved by 2 classes from randomization	5 4.6%	3 5.9%
6 Months: Improved by 1 class from randomization	54 49.5%	43 84.3%
6 Months: No change from randomization	200 183.5%	205 402%
6 Months: Worsened by 1 class from randomization	52 47.7%	41 80.4%
6 Months: Worsened by 2 classes from randomization	1 0.9%	1 2%
6 Months: Comparative data not available	37 33.9%	49 96.1%
12 Months:Improved by 2 classes from randomization	4 3.7%	5 9.8%
12 Months:Improved by 1 class from randomization	54 49.5%	34 66.7%
12 Months: No change from randomization	172 157.8%	172 337.3%
12 Months: Worsened by 1 class from randomization	49 45%	64 125.5%
12 Months:Worsened by 2 classes from randomization	2 1.8%	3 5.9%
12 Months: Comparative data not available	68 62.4%	64 125.5%
18 Months:Improved by 2 classes from randomization	3 2.8%	2 3.9%
18 Months: Improved by 1 class from randomization	43 39.4%	45 88.2%
18 Months: No change from randomization	142 130.3%	141 276.5%
18 Months: Worsened by 1 class from randomization	50 45.9%	56 109.8%
18 Months:Worsened by 2 classes from randomization	4 3.7%	6 11.8%
18 Months: Comparative data not available	107 98.2%	92 180.4%
24 Months:Improved by 2 classes from randomization	2 1.8%	3 5.9%
24 Months: Improved by 1 class from randomization	35 32.1%	36 70.6%
24 Months: No change from randomization	135 123.9%	126 247.1%
24 Months:Worsened by 1 class from randomization	41 37.6%	54 105.9%
24 Months:Worsened by 2 classes from randomization	4 3.7%	3 5.9%
24 Months: Comparative data not available	132 121.1%	120 235.3%

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Biventricular Pacing Arm, Right Ventricular Pacing Arm
	Comments	Subjects' changes in NYHA classification from randomization to 6 months were determined. The null hypothesis was that the average change among patients with biventricular pacing is equal to that of patients with right ventricular pacing.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value	0.591
	Comments	BLOCK HF is a Bayesian study; thus p-values were not used. Instead, a posterior probability, representing the probability that subjects with biventricular pacing have better outcomes at 6 months, was calculated. A probability ≥0.95 was significant.
	Method	Posterior Distribution for Average Rank
	Comments	Subjects' Randomization - 6 month changes in NYHA classification were ranked. The BiV - RV difference in average rank was analyzed.
Method of Estimation	Estimation Parameter	BiV - RV Difference in Average Rank
	Estimated Value	0.012
	Confidence Interval	(2-Sided) 95%; to
	Parameter Dispersion	Type: Value:
	Estimation Comments	Positive values reflect better outcomes over time in the BiV arm than the RV arm.

Statistical Analysis 2

Statistical Analysis Overview	Comparison Group Selection	Biventricular Pacing Arm, Right Ventricular Pacing Arm
	Comments	Subjects' changes in NYHA classification from randomization to 12 months were determined. The null hypothesis was that the average change among patients with biventricular pacing is equal to that of patients with right ventricular pacing.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value	0.986
	Comments	BLOCK HF is a Bayesian study; thus p-values were not used. Instead, a posterior probability,representing the probability that subjects with biventricular pacing have better outcomes at 12 months, was calculated. A probability ≥0.95 was significant.
	Method	Posterior Distribution for Average Rank
	Comments	Subjects' Randomization - 12 month changes in NYHA classification were ranked. The BiV - RV difference in average rank was analyzed.
Method of Estimation	Estimation Parameter	BiV - RV Difference in Average Rank
	Estimated Value	0.126
	Confidence Interval	(2-Sided) 95%; to
	Parameter Dispersion	Type: Value:
	Estimation Comments	Positive values reflect better outcomes over time in the BiV arm than the RV arm.

Statistical Analysis 3

Statistical Analysis Overview	Comparison Group Selection	Biventricular Pacing Arm, Right Ventricular Pacing Arm
	Comments	Subjects' changes in NYHA classification from randomization to 18 months were determined. The null hypothesis was that the average change among patients with biventricular pacing is equal to that of patients with right ventricular pacing.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value	0.726
	Comments	BLOCK HF is a Bayesian study; thus p-values were not used. Instead, a posterior probability,representing the probability that subjects with biventricular pacing have better outcomes at 12 months, was calculated. A probability ≥0.95 was significant.
	Method	Posterior Distribution for Average Rank
	Comments	Subjects' Randomization - 18 month changes in NYHA classification were ranked. The BiV - RV difference in average rank was analyzed.
Method of Estimation	Estimation Parameter	BiV - RV Difference in Average Rank
	Estimated Value	0.039
	Confidence Interval	(2-Sided) 95%; to
	Parameter Dispersion	Type: Value:
	Estimation Comments	Positive values reflect better outcomes over time in the BiV arm than the RV arm.

Statistical Analysis 4

Statistical Analysis Overview	Comparison Group Selection	Biventricular Pacing Arm, Right Ventricular Pacing Arm
	Comments	Subjects' changes in NYHA classification from randomization to 24 months were determined. The null hypothesis was that the average change among patients with biventricular pacing is equal to that of patients with right ventricular pacing.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value	0.701
	Comments	BLOCK HF is a Bayesian study; thus p-values were not used. Instead, a posterior probability,representing the probability that subjects with biventricular pacing have better outcomes at 24 months, was calculated. A probability ≥0.95 was significant.
	Method	Posterior Distribution for Average Rank
	Comments	Subjects' Randomization - 24 month changes in NYHA classification were ranked. The BiV - RV difference in average rank was analyzed.
Method of Estimation	Estimation Parameter	BiV - RV Difference in Average Rank
	Estimated Value	0.035
	Confidence Interval	(2-Sided) 95%; to
	Parameter Dispersion	Type: Value:
	Estimation Comments	Positive values reflect better outcomes over time in the BiV arm than the RV arm.

8. Secondary Outcome

Title	Change in Heart Failure Stage
Description	The endpoint is a subject's change in Heart Failure Stage (a measure of the degree of heart failure a subject has on a 4 stage scale (A, B, C, D), with Class A being the healthiest score and Class D being the sickest score) from randomization to each of four time points: 6 months, 12 months, 18 months, and 24 months.
Time Frame	Randomization to 24 Months

Outcome Measure Data

Analysis Population Description

For each time point(e.g. 6 months), only subjects with HF Stage assessed at randomization and that time point were included in the analysis. Those who could not be analyzed at a time point(for reasons such as death, exit,missed visit,or HF Stage not assessed) are listed under the "Comparative data not available" category for that time point.

Arm/Group Title	Biventricular Pacing Arm	Right Ventricular Pacing Arm
Arm/Group Description	Subjects randomized to receive biventricular pacing	Subjects randomized to receive right ventricular pacing.
Measure Participants	349	342
6 Months: Improved by 2 stages since randomization	1 0.9%	0 0%
6 Months: Improved by 1 stage since randomization	11 10.1%	5 9.8%
6 Months: No change from randomization	296 271.6%	274 537.3%
6 Months: Worsened by 1 stage since randomization	2 1.8%	14 27.5%
6 Months: Worsened by 2 stages since randomization	1 0.9%	0 0%
6 Months: Comparative data not available	38 34.9%	49 96.1%
12 Months:Improved by 2 stages since randomization	0 0%	0 0%
12 Months:Improved by 1 stage since randomization	7 6.4%	8 15.7%
12 Months: No change since randomization	258 236.7%	244 478.4%
12 Months: Worsened by 1 stage since randomization	15 13.8%	23 45.1%
12 Months:Worsened by 2 stages since randomization	1 0.9%	1 2%
12 Months: Comparative data not available	68 62.4%	66 129.4%
18 Months:Improved by 2 stages since randomization	0 0%	0 0%
18 Months:Improved by 1 stage since randomization	4 3.7%	5 9.8%
18 Months: No change since randomization	222 203.7%	225 441.2%
18 Months:Worsened by 1 stage since randomization	16 14.7%	18 35.3%
18 Months:Worsened by 2 stages since randomization	0 0%	1 2%
18 Months: Comparative data not available	107 98.2%	93 182.4%
24 Months:Improved by 2 stages since randomization	0 0%	0 0%
24 Months: Improved by 1 stage since randomization	4 3.7%	6 11.8%
24 Months: No change since randomization	196 179.8%	197 386.3%
24 Months:Worsened by 1 stage since randomization	16 14.7%	19 37.3%
24 Months:Worsened by 2 stages since randomization	1 0.9%	0 0%
24 Months: Comparative data not available	132 121.1%	120 235.3%

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Biventricular Pacing Arm, Right Ventricular Pacing Arm
	Comments	Subjects' changes in HF stage from randomization to 6 months were determined. The null hypothesis was that the average change among patients with biventricular pacing is equal to that of patients with right ventricular pacing.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value	0.534
	Comments	BLOCK HF is a Bayesian study; thus p-values were not used. Instead, a posterior probability, representing the probability that subjects with biventricular pacing have better outcomes at 6 months, was calculated. A probability ≥0.95 was significant.
	Method	Posterior Distribution for Average Rank
	Comments	Subjects' Randomization - 6 month change in HF Stage were ranked. The BiV - RV difference in average rank was analyzed.
Method of Estimation	Estimation Parameter	BiV - RV Difference in Average Rank
	Estimated Value	0.002
	Confidence Interval	(2-Sided) 95%; to
	Parameter Dispersion	Type: Value:
	Estimation Comments	Positive values reflect better outcomes over time in the BiV arm than the RV arm.

Statistical Analysis 2

Statistical Analysis Overview	Comparison Group Selection	Biventricular Pacing Arm, Right Ventricular Pacing Arm
	Comments	Subjects' change in HF stage from randomization to 12 months were determined. The null hypothesis was that the average change among patients with biventricular pacing is equal to that of patients with right ventricular pacing.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value	0.825
	Comments	BLOCK HF is a Bayesian study; thus p-values were not used. Instead, a posterior probability,representing the probability that subjects with biventricular pacing have better outcomes at 12 months, was calculated. A probability ≥0.95 was significant.
	Method	Posterior Distribution for Average Rank
	Comments	Subjects' Randomization - 12 month changes in HF Stage were ranked. The BiV - RV difference in average rank was analyzed.
Method of Estimation	Estimation Parameter	BiV - RV Difference in Average Rank
	Estimated Value	0.026
	Confidence Interval	(2-Sided) 95%; to
	Parameter Dispersion	Type: Value:
	Estimation Comments	Positive values reflect better outcomes over time in the BiV arm than the RV arm.

Statistical Analysis 3

Statistical Analysis Overview	Comparison Group Selection	Biventricular Pacing Arm, Right Ventricular Pacing Arm
	Comments	Subjects' changes in HF stage from randomization to 18 months were determined. The null hypothesis was that the average change among patients with biventricular pacing is equal to that of patients with right ventricular pacing.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value	0.651
	Comments	BLOCK HF is a Bayesian study; thus p-values were not used. Instead, a posterior probability,representing the probability that subjects with biventricular pacing have better outcomes at 18 months, was calculated. A probability ≥0.95 was significant.
	Method	Posterior Distribution for Average Rank
	Comments	Subjects' Randomization - 18 month changes in HF Stage were ranked. The BiV - RV difference in average rank was analyzed.
Method of Estimation	Estimation Parameter	BiV - RV Difference in Average Rank
	Estimated Value	0.010
	Confidence Interval	(2-Sided) 95%; to
	Parameter Dispersion	Type: Value:
	Estimation Comments	Positive values denote that the BiV arm had better outcomes over time than the RV arm.

Statistical Analysis 4

Statistical Analysis Overview	Comparison Group Selection	Biventricular Pacing Arm, Right Ventricular Pacing Arm
	Comments	Subjects' changes in HF stage from randomization to 24 months were determined. The null hypothesis was that the average change among patients with biventricular pacing is equal to that of patients with right ventricular pacing.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value	0.425
	Comments	BLOCK HF is a Bayesian study; thus p-values were not used. Instead, a posterior probability,representing the probability that subjects with biventricular pacing have better outcomes at 24 months, was calculated. A probability ≥0.95 was significant.
	Method	Posterior Distribution for Average Rank
	Comments	Subjects' Randomization - 24 month changes in HF Stage were ranked. The BiV - RV difference in average rank was analyzed.
Method of Estimation	Estimation Parameter	BiV - RV Difference in Average Rank
	Estimated Value	-0.006
	Confidence Interval	(2-Sided) 95%; to
	Parameter Dispersion	Type: Value:
	Estimation Comments	Positive values denote better outcomes over time in the BiV arm than the RV arm.

9. Secondary Outcome

Title	Change in Cardiovascular Medications
Description	The endpoints are what classes of drugs (e.g. Beta blockers, Diuretics, Nitrates, etc.) each subject was on at the time of scheduled visits (e.g Randomization, 6 months, 12 months, etc.)
Time Frame	Participants were followed for the duration of the study, an average of 39.8 months post-randomization.

Outcome Measure Data

Analysis Population Description

Because indications for defibrillation devices like CRT-Ds are defined by characteristics that relate to medication guidelines, medication results are presented separately for each device group. Medications were assessed only for subjects who completed visits (denoted as "Subjects with Medications Assessed").

Arm/Group Title	CRT-P: Biventricular Pacing Arm	CRT-P: Right Ventricular Pacing Arm	CRT-D: Biventricular Pacing Arm	CRT-D: Right Ventricular Pacing Arm
Arm/Group Description	Subjects implanted with a CRT-P device and randomized to receive biventricular pacing	Subjects implanted with a CRT-D device and randomized to receive right ventricular pacing.	Subjects implanted with a CRT-D device and randomized to receive biventricular pacing	Subjects implanted with a CRT-D device and randomized to receive right ventricular pacing
Measure Participants	243	241	106	101
Randomization: Subjects on ACE-Inhibitors/ARBs	173 158.7%	179 351%	93 38.3%	84 34.9%
Randomization: Subjects on Beta Blockers	186 170.6%	191 374.5%	98 40.3%	93 38.6%
Randomization: Subjects on Vasodilators/Nitrates	53 48.6%	44 86.3%	31 12.8%	20 8.3%
Randomization: Subjects on Aldosterone Antagonists	33 30.3%	25 49%	19 7.8%	25 10.4%
Randomization: Subjects on Diuretics	156 143.1%	158 309.8%	74 30.5%	74 30.7%
6 Months: Subjects with Medications Assessed	226 207.3%	207 405.9%	94 38.7%	89 36.9%
6 Months: Subjects on ACE-Inhibitors/ARBs	162 148.6%	152 298%	77 31.7%	73 30.3%
6 Months: Subjects on Beta Blockers	175 160.6%	171 335.3%	87 35.8%	79 32.8%
6 Months: Subjects on Vasodilators/Nitrates	46 42.2%	42 82.4%	24 9.9%	12 5%
6 Months: Subjects on Aldosterone Antagonists	31 28.4%	21 41.2%	20 8.2%	25 10.4%
6 Months: Subjects on Diuretics	148 135.8%	137 268.6%	66 27.2%	70 29%
12 Months: Subjects with Medications Assessed	205 188.1%	200 392.2%	83 34.2%	81 33.6%
12 Months: Subjects on ACE-Inhibitors/ARBs	147 134.9%	151 296.1%	72 29.6%	70 29%
12 Months: Subjects on Beta Blockers	158 145%	170 333.3%	79 32.5%	75 31.1%
12 Months: Subjects on Vasodilators/Nitrates	45 41.3%	43 84.3%	22 9.1%	13 5.4%
12 Months: Subjects on Aldosterone Antagonists	23 21.1%	20 39.2%	13 5.3%	21 8.7%
12 Months: Subjects on Diuretics	133 122%	131 256.9%	57 23.5%	60 24.9%
18 Months: Subjects with Medications Assessed	169 155%	181 354.9%	78 32.1%	72 29.9%
18 Months: Subjects on ACE-Inhibitors/ARBs	121 111%	137 268.6%	62 25.5%	58 24.1%
18 Months: Subjects on Beta Blockers	134 122.9%	152 298%	75 30.9%	63 26.1%
18 Months: Subjects on Vasodilators/Nitrates	36 33%	44 86.3%	22 9.1%	11 4.6%
18 Months: Subjects on Aldosterone Antagonists	16 14.7%	21 41.2%	9 3.7%	20 8.3%
18 Months: Subjects on Diuretics	111 101.8%	125 245.1%	51 21%	59 24.5%
24 Months: Subjects with Medications Assessed	152 139.4%	157 307.8%	69 28.4%	67 27.8%
24 Months: Subjects on ACE-Inhibitors/ARBs	114 104.6%	119 233.3%	58 23.9%	56 23.2%
24 Months: Subjects on Beta Blockers	118 108.3%	133 260.8%	65 26.7%	63 26.1%
24 Months: Subjects on Vasodilators/Nitrates	28 25.7%	37 72.5%	23 9.5%	10 4.1%
24 Months: Subjects on Aldosterone Antagonists	18 16.5%	15 29.4%	13 5.3%	18 7.5%
24 Months: Subjects on Diuretics	97 89%	104 203.9%	47 19.3%	56 23.2%
30 Months: Subjects with Medications Assessed	130 119.3%	131 256.9%	53 21.8%	57 23.7%
30 Months: Subjects on ACE-Inhibitors/ARBs	92 84.4%	102 200%	42 17.3%	47 19.5%
30 Months: Subjects on Beta Blockers	104 95.4%	114 223.5%	51 21%	56 23.2%
30 Months: Subjects on Vasodilators/Nitrates	23 21.1%	28 54.9%	16 6.6%	11 4.6%
30 Months: Subjects on Aldosterone Antagonists	14 12.8%	14 27.5%	10 4.1%	15 6.2%
30 Months: Subjects on Diuretics	82 75.2%	90 176.5%	36 14.8%	50 20.7%
36 Months: Subjects with Medications Assessed	109 100%	112 219.6%	42 17.3%	44 18.3%
36 Months: Subjects on ACE-Inhibitors/ARBs	76 69.7%	85 166.7%	30 12.3%	37 15.4%
36 Months: Subjects on Beta Blockers	86 78.9%	97 190.2%	41 16.9%	44 18.3%
36 Months: Subjects on Vasodilators/Nitrates	21 19.3%	24 47.1%	14 5.8%	9 3.7%
36 Months: Subjects on Aldosterone Antagonists	10 9.2%	19 37.3%	8 3.3%	10 4.1%
36 Months: Subjects on Diuretics	69 63.3%	79 154.9%	34 14%	37 15.4%
42 Months: Subjects with Medications Assessed	94 86.2%	99 194.1%	38 15.6%	42 17.4%
42 Months: Subjects on ACE-Inhibitors/ARBs	69 63.3%	73 143.1%	27 11.1%	35 14.5%
42 Months: Subjects on Beta Blockers	75 68.8%	86 168.6%	35 14.4%	42 17.4%
42 Months: Subjects on Vasodilators/Nitrates	15 13.8%	22 43.1%	12 4.9%	10 4.1%
42 Months: Subjects on Aldosterone Antagonists	8 7.3%	13 25.5%	9 3.7%	12 5%
42 Months: Subjects on Diuretics	57 52.3%	71 139.2%	31 12.8%	39 16.2%

10. Secondary Outcome

Title	Frequency of Adverse Events Post-randomization
Description	Adverse events that subjects experienced after they were randomized were compared between arms with regard to several categories such as heart failure (HF)-relatedness, relatedness to the implant procedure, and relatedness to the implanted system, including individual components such as the left ventricular (LV) lead and the CRT-P or CRT-D generator.
Time Frame	Participants were followed for the duration of the study, an average of 39.8 months post-randomization.

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	CRT-P: Biventricular Pacing Arm	CRT-P: Right Ventricular Pacing Arm	CRT-D: Biventricular Pacing Arm	CRT-D: Right Ventricular Pacing Arm
Arm/Group Description	Subjects implanted with a CRT-P device and randomized to receive biventricular pacing	Subjects implanted with a CRT-D device and randomized to receive right ventricular pacing.	Subjects implanted with a CRT-D device and randomized to receive biventricular pacing	Subjects implanted with a CRT-D device and randomized to receive right ventricular pacing
Measure Participants	243	241	106	101
Subjects with procedure-related AE(s)	37 33.9%	7 13.7%	7 2.9%	2 0.8%
Subjects with system-related AE(s)	56 51.4%	31 60.8%	47 19.3%	24 10%
Subjects with LV lead-related AE(s)	40 36.7%	12 23.5%	14 5.8%	4 1.7%
Subjects with CRT-P/CRT-D related AE(s)	12 11%	17 33.3%	36 14.8%	18 7.5%
Subjects with HF-related AE(s)	73 67%	106 207.8%	45 18.5%	47 19.5%

11. Secondary Outcome

Title	Cardiovascular-related Healthcare Utilizations
Description	Cardiovascular-related healthcare utilizations (HCUs), such as hospitalizations, Emergency Department visits, urgent care visits, and clinic visits that subjects experienced after being randomized were summarized for each randomization arm
Time Frame	Participants were followed for the duration of the study, an average of 39.8 months post-randomization.

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Biventricular Pacing Arm	Right Ventricular Pacing Arm
Arm/Group Description	Subjects randomized to receive biventricular pacing	Subjects randomized to receive right ventricular pacing.
Measure Participants	349	342
Subjects with a post-randomization CV HCU	264 242.2%	263 515.7%
Subjects with post-randomization hospitalization	164 150.5%	162 317.6%
Subjects with post-randomization ED visit	118 108.3%	128 251%
Subjects with post-randomization urgent care visit	12 11%	12 23.5%
Subjects with post-randomization clinic visit	214 196.3%	220 431.4%

12. Secondary Outcome

Title	Change in Quality of Life at 6 Months
Description	The endpoint will be a subject's change in Quality of Life score from randomization to 6 months. The Quality of Life score at a time point is calculated using the Minnesota Living with Heart Failure Questionnaire, which consists of 21 questions each on a 6 point scale from 0 to 5. The 21 scores are added up and the final score, ranging from 0 (best) to 105 (worst) is the subject's quality of life score. For each subject the measure will be the randomization visit - 6 month difference in QOL score, with positive values denoting a reduction in score and improvement in Quality of Life. Subjects with missing QOL scores at one or both time points were excluded from analysis, and so the number of subjects analyzed for this outcome was a subset of the number of randomized subjects.
Time Frame	Randomization to 6 Months

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Biventricular Pacing Arm	Right Ventricular Pacing Arm
Arm/Group Description	Subjects randomized to receive biventricular pacing	Subjects randomized to receive right ventricular pacing.
Measure Participants	304	289
Mean (Standard Deviation) [units on a scale]	5 (20.3)	0.3 (19.4)

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Biventricular Pacing Arm, Right Ventricular Pacing Arm
	Comments	The null hypothesis is that patients with AV block, ejection fractions of at most 50%, and NYHA classifications of I, II, or III who receive biventricular pacing have the same average change in QOL score from randomization to 6 months as corresponding patients who receive right ventricular pacing. This was tested against the hypothesis that patients with biventricular pacing have a greater reduction (and thus improvement) in QOL score at 6 months than patients with right ventricular pacing.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value	0.9976
	Comments	BLOCK HF is a Bayesian study; a p-value was not used. Instead, a posterior probability, representing the probability that patients with BiV pacing have better outcomes than those with RV pacing, was calculated. A probability ≥0.95 was significant.
	Method	Posterior Probability of Mean QOL Change
	Comments	The posterior distribution for the BiV - RV difference in mean QOL score improvement from randomization to 6 months was determined.
Method of Estimation	Estimation Parameter	Mean Difference (Final Values)
	Estimated Value	4.7
	Confidence Interval	(2-Sided) 95%; to
	Parameter Dispersion	Type: Value:
	Estimation Comments

13. Secondary Outcome

Title	Change in Quality of Life at 12 Months
Description	The endpoint will be a subject's change in Quality of Life score from randomization to 12 months. The Quality of Life score at a time point is calculated using the Minnesota Living with Heart Failure Questionnaire, which consists of 21 questions each on a 6 point scale from 0 to 5. The 21 scores are added up and the final score, ranging from 0 (best) to 105 (worst) is the subject's quality of life score. For each subject the measure will be the randomization visit - 12 month difference in QOL score, with positive values denoting a reduction in score and improvement in Quality of Life. Subjects with missing QOL scores at one or both time points were excluded from analysis, and so the number of subjects analyzed for this outcome was a subset of the number of randomized subjects.
Time Frame	Randomization to 12 months

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Biventricular Pacing Arm	Right Ventricular Pacing Arm
Arm/Group Description	Subjects randomized to receive biventricular pacing	Subjects randomized to receive right ventricular pacing.
Measure Participants	274	273
Mean (Standard Deviation) [units on a scale]	3.9 (20.1)	0.9 (18.9)

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Biventricular Pacing Arm, Right Ventricular Pacing Arm
	Comments	The null hypothesis is that patients with AV block, ejection fractions of at most 50%, and NYHA classifications of I, II, or III who receive biventricular pacing have the same average change in QOL score from randomization to 12 months as corresponding patients who receive right ventricular pacing. This was tested against the hypothesis that patients with biventricular pacing have a greater reduction (and thus improvement) in QOL score at 12 months than patients with right ventricular pacing.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value	0.9641
	Comments	BLOCK HF is a Bayesian study; a p-value was not used. Instead, a posterior probability, representing the probability that patients with BiV pacing have better outcomes than those with RV pacing, was calculated. A probability ≥0.95 was significant.
	Method	Posterior Probability of Mean QOL Change
	Comments	The posterior distribution for the BiV - RV difference in mean QOL score improvement from randomization to 12 months was determined.
Method of Estimation	Estimation Parameter	Mean Difference (Final Values)
	Estimated Value	3.0
	Confidence Interval	(2-Sided) 95%; to
	Parameter Dispersion	Type: Value:
	Estimation Comments

14. Secondary Outcome

Title	Change in Quality of Life at 18 Months
Description	The endpoint will be a subject's change in Quality of Life score from randomization to 18 months. The Quality of Life score at a time point is calculated using the Minnesota Living with Heart Failure Questionnaire, which consists of 21 questions each on a 6 point scale from 0 to 5. The 21 scores are added up and the final score, ranging from 0 (best) to 105 (worst) is the subject's quality of life score. For each subject the measure will be the randomization visit - 18 month difference in QOL score, with positive values denoting a reduction in score and improvement in Quality of Life. Subjects with missing QOL scores at one or both time points were excluded from analysis, and so the number of subjects analyzed for this outcome was a subset of the number of randomized subjects.
Time Frame	Randomization to 18 Months

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Biventricular Pacing Arm	Right Ventricular Pacing Arm
Arm/Group Description	Subjects randomized to receive biventricular pacing	Subjects randomized to receive right ventricular pacing.
Measure Participants	237	244
Mean (Standard Deviation) [units on a scale]	2.3 (20.5)	0.5 (18.1)

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Biventricular Pacing Arm, Right Ventricular Pacing Arm
	Comments	The null hypothesis is that patients with AV block, ejection fractions of at most 50%, and NYHA classifications of I, II, or III who receive biventricular pacing have the same average change in QOL score from randomization to 18 months as corresponding patients who receive right ventricular pacing. This was tested against the hypothesis that patients with biventricular pacing have a greater reduction (and thus improvement) in QOL score at 18 months than patients with right ventricular pacing.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value	0.8416
	Comments	BLOCK HF is a Bayesian study; a p-value was not used. Instead, a posterior probability, representing the probability that patients with BiV pacing have better outcomes than those with RV pacing, was calculated. A probability ≥0.95 was significant.
	Method	Posterior Probability of Mean QOL Change
	Comments	The parameter of interest was the BiV - RV difference in mean QOL change from randomization to 18 months.
Method of Estimation	Estimation Parameter	Mean Difference (Final Values)
	Estimated Value	1.8
	Confidence Interval	(2-Sided) 95%; to
	Parameter Dispersion	Type: Value:
	Estimation Comments

15. Secondary Outcome

Title	Change in Quality of Life at 24 Months
Description	The endpoint will be a subject's change in Quality of Life score from randomization to 24 months. The Quality of Life score at a time point is calculated using the Minnesota Living with Heart Failure Questionnaire, which consists of 21 questions each on a 6 point scale from 0 to 5. The 21 scores are added up and the final score, ranging from 0 (best) to 105 (worst) is the subject's quality of life score. For each subject the measure will be the randomization visit - 24 month difference in QOL score, with positive values denoting a reduction in score and improvement in Quality of Life. Subjects with missing QOL scores at one or both time points were excluded from analysis, and so the number of subjects analyzed for this outcome was a subset of the number of randomized subjects.
Time Frame	Randomization to 24 Months

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Biventricular Pacing Arm	Right Ventricular Pacing Arm
Arm/Group Description	Subjects randomized to receive biventricular pacing	Subjects randomized to receive right ventricular pacing.
Measure Participants	214	218
Mean (Standard Deviation) [units on a scale]	2.6 (20.5)	1.5 (18.8)

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Biventricular Pacing Arm, Right Ventricular Pacing Arm
	Comments	The null hypothesis is that patients with AV block, ejection fractions of at most 50%, and NYHA classifications of I, II, or III who receive biventricular pacing have the same average change in QOL score from randomization to 24 months as corresponding patients who receive right ventricular pacing. This was tested against the hypothesis that patients with biventricular pacing have a greater reduction (and thus improvement) in QOL score at 24 months than patients with right ventricular pacing.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value	0.7270
	Comments	BLOCK HF is a Bayesian study; a p-value was not used. Instead, a posterior probability, representing the probability that patients with BiV pacing have better outcomes than those with RV pacing, was calculated. A probability ≥0.95 was significant.
	Method	Posterior Probability of Mean QOL Change
	Comments	The posterior distribution for the BiV - RV difference in mean QOL score improvement from randomization to 24 months was determined.
Method of Estimation	Estimation Parameter	Mean Difference (Final Values)
	Estimated Value	1.1
	Confidence Interval	(2-Sided) 95%; to
	Parameter Dispersion	Type: Value:
	Estimation Comments

16. Secondary Outcome

Title	Change in Left Ventricular Ejection Fraction (LVEF) From Randomization to 6 Months
Description	The endpoint will be a subject's change in LV Ejection Fraction (a measure of the percentage of blood ejected from the left ventricle of the heart with each contraction). A normal range is 55% to 70%. For each subject the measure will be the 6 month - randomization visit difference in LVEF value.
Time Frame	Randomization to 6 Months

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Biventricular Pacing Arm	Right Ventricular Pacing Arm
Arm/Group Description	Subjects randomized to receive biventricular pacing	Subjects randomized to receive right ventricular pacing.
Measure Participants	282	273
Mean (Standard Deviation) [percentage]	3.0 (8.4)	-0.3 (8.9)

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Biventricular Pacing Arm, Right Ventricular Pacing Arm
	Comments	The null hypothesis is that patients with AV block, ejection fractions of at most 50%, and NYHA classifications of I, II, or III who receive biventricular pacing have the same average change in LVEF from randomization to 6 months as corresponding patients who receive right ventricular pacing. This was tested against the hypothesis that patients with biventricular pacing have a different change in LVEF from randomization to 6 months than patients with right ventricular pacing.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value
	Comments
	Method
	Comments
Method of Estimation	Estimation Parameter	Posterior BiV - RV Mean Difference
	Estimated Value	3.334
	Confidence Interval	(2-Sided) 95%; 1.886 to 4.815
	Parameter Dispersion	Type: Value:
	Estimation Comments	Because Bayesian analyses were employed, a 95% two-sided credible interval was used instead of a confidence interval. This reflects the 2.5th and 97.5th percentile of possible values for the BiV-RV difference in mean LVEF change through 6 months.

17. Secondary Outcome

Title	Change in Left Ventricular Ejection Fraction (LVEF) From Randomization to 12 Months
Description	The endpoint will be a subject's change in LV Ejection Fraction (a measure of the percentage of blood ejected from the left ventricle of the heart with each contraction). A normal range is 55% to 70%. For each subject the measure will be the 12 month - randomization visit difference in LVEF value.
Time Frame	Randomization to 12 Months

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Biventricular Pacing Arm	Right Ventricular Pacing Arm
Arm/Group Description	Subjects randomized to receive biventricular pacing	Subjects randomized to receive right ventricular pacing.
Measure Participants	263	260
Mean (Standard Deviation) [percentage]	2.7 (9.3)	-0.5 (9.4)

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Biventricular Pacing Arm, Right Ventricular Pacing Arm
	Comments	The null hypothesis is that patients with AV block, ejection fractions of at most 50%, and NYHA classifications of I, II, or III who receive biventricular pacing have the same average change in LVEF from randomization to 12 months as corresponding patients who receive right ventricular pacing. This was tested against the hypothesis that patients with biventricular pacing have a different change in LVEF from randomization to 12 months than patients with right ventricular pacing.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value
	Comments
	Method
	Comments
Method of Estimation	Estimation Parameter	Posterior BiV - RV Mean Difference
	Estimated Value	3.232
	Confidence Interval	(2-Sided) 95%; 1.618 to 4.839
	Parameter Dispersion	Type: Value:
	Estimation Comments	Because Bayesian analyses were employed, a 95% two-sided credible interval was used instead of a confidence interval. This reflects the 2.5th and 97.5th percentile of possible values for the BiV-RV difference in mean LVEF change through 12 months.

18. Secondary Outcome

Title	Change in Left Ventricular Ejection Fraction (LVEF) From Randomization to 18 Months
Description	The endpoint will be a subject's change in LV Ejection Fraction (a measure of the percentage of blood ejected from the left ventricle of the heart with each contraction). A normal range is 55% to 70%. For each subject the measure will be the 18 month - randomization visit difference in LVEF value.
Time Frame	Randomization to 18 Months

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Biventricular Pacing Arm	Right Ventricular Pacing Arm
Arm/Group Description	Subjects randomized to receive biventricular pacing	Subjects randomized to receive right ventricular pacing.
Measure Participants	223	226
Mean (Standard Deviation) [percentage]	2.7 (9.5)	0.4 (10.1)

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Biventricular Pacing Arm, Right Ventricular Pacing Arm
	Comments	The null hypothesis is that patients with AV block, ejection fractions of at most 50%, and NYHA classifications of I, II, or III who receive biventricular pacing have the same average change in LVEF from randomization to 18 months as corresponding patients who receive right ventricular pacing. This was tested against the hypothesis that patients with biventricular pacing have a different change in LVEF from randomization to 18 months than patients with right ventricular pacing.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value
	Comments
	Method
	Comments
Method of Estimation	Estimation Parameter	Posterior BiV - RV Mean Difference
	Estimated Value	2.240
	Confidence Interval	(2-Sided) 95%; 0.419 to 4.066
	Parameter Dispersion	Type: Value:
	Estimation Comments	Because Bayesian analyses were employed, a 95% two-sided credible interval was used instead of a confidence interval. This reflects the 2.5th and 97.5th percentile of possible values for the BiV-RV difference in mean LVEF change through 18 months.

19. Secondary Outcome

Title	Change in Left Ventricular Ejection Fraction (LVEF) From Randomization to 24 Months
Description	The endpoint will be a subject's change in LV Ejection Fraction (a measure of the percentage of blood ejected from the left ventricle of the heart with each contraction). A normal range is 55% to 70%. For each subject the measure will be the 24 month - randomization visit difference in LVEF value.
Time Frame	Randomization to 24 Months

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Biventricular Pacing Arm	Right Ventricular Pacing Arm
Arm/Group Description	Subjects randomized to receive biventricular pacing	Subjects randomized to receive right ventricular pacing.
Measure Participants	192	205
Mean (Standard Deviation) [percentage]	2.0 (9.6)	-1.6 (10.5)

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Biventricular Pacing Arm, Right Ventricular Pacing Arm
	Comments	The null hypothesis is that patients with AV block, ejection fractions of at most 50%, and NYHA classifications of I, II, or III who receive biventricular pacing have the same average change in LVEF from randomization to 24 months as corresponding patients who receive right ventricular pacing. This was tested against the hypothesis that patients with biventricular pacing have a different change in LVEF from randomization to 24 months than patients with right ventricular pacing.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value
	Comments
	Method
	Comments
Method of Estimation	Estimation Parameter	Posterior BiV - RV Mean Difference
	Estimated Value	3.623
	Confidence Interval	(2-Sided) 95%; 1.623 to 5.604
	Parameter Dispersion	Type: Value:
	Estimation Comments	Because Bayesian analyses were employed, a 95% two-sided credible interval was used instead of a confidence interval. This reflects the 2.5th and 97.5th percentile of possible values for the BiV-RV difference in mean LVEF change through 24 months.

20. Secondary Outcome

Title	Change in Left Ventricular End Systolic Volume Index (LVESVI) From Randomization to 6 Months
Description	The endpoint will be a subject's change in Left Ventricular End Systolic Volume Index (a measure of the volume of blood in the left ventricle at the end of systole, normalized over body surface area). In other words, a measure of the size of the left ventricle. For each subject the measure is the 6 month - randomization visit difference in LVESVI. Negative values correspond to reductions in LVESVI over time.
Time Frame	Randomization to 6 Months

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Biventricular Pacing Arm	Right Ventricular Pacing Arm
Arm/Group Description	Subjects randomized to receive biventricular pacing	Subjects randomized to receive right ventricular pacing.
Measure Participants	279	272
Mean (Standard Deviation) [ml/square meter of body surface area]	-6.8 (17.1)	0.4 (17.7)

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Biventricular Pacing Arm, Right Ventricular Pacing Arm
	Comments	The null hypothesis is that patients with AV block, ejection fractions of at most 50%, and NYHA classifications of I, II, or III who receive biventricular pacing have the same average change in LVESVI from randomization to 6 months as corresponding patients who receive right ventricular pacing. This was tested against the hypothesis that patients with biventricular pacing have a different change in LVESVI from randomization to 6 months than patients with right ventricular pacing.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value
	Comments
	Method
	Comments
Method of Estimation	Estimation Parameter	Posterior BiV - RV Mean Difference
	Estimated Value	-7.204
	Confidence Interval	(2-Sided) 95%; -10.12 to -4.214
	Parameter Dispersion	Type: Value:
	Estimation Comments	Because Bayesian analyses were employed, a 95% two-sided credible interval was used instead of a confidence interval. This reflects the 2.5th and 97.5th percentile of possible values for the BiV-RV difference in mean LVESVI change through 6 months.

21. Secondary Outcome

Title	Change in Left Ventricular End Systolic Volume Index (LVESVI) From Randomization to 12 Months
Description	The endpoint will be a subject's change in Left Ventricular End Systolic Volume Index (a measure of the volume of blood in the left ventricle at the end of systole, normalized over body surface area). In other words, a measure of the size of the left ventricle. For each subject the measure is the 12 month - randomization visit difference in LVESVI. Negative values correspond to reductions in LVESVI over time.
Time Frame	Randomization to 12 Months

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Biventricular Pacing Arm	Right Ventricular Pacing Arm
Arm/Group Description	Subjects randomized to receive biventricular pacing	Subjects randomized to receive right ventricular pacing.
Measure Participants	260	256
Mean (Standard Deviation) [ml/square meter of body surface area]	-6.8 (18.7)	0.5 (20.2)

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Biventricular Pacing Arm, Right Ventricular Pacing Arm
	Comments	The null hypothesis is that patients with AV block, ejection fractions of at most 50%, and NYHA classifications of I, II, or III who receive biventricular pacing have the same average change in LVESVI from randomization to 12 months as corresponding patients who receive right ventricular pacing. This was tested against the hypothesis that patients with biventricular pacing have a different change in LVESVI from randomization to 12 months than patients with right ventricular pacing.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value
	Comments
	Method
	Comments
Method of Estimation	Estimation Parameter	Posterior BiV - RV Mean Difference
	Estimated Value	-7.255
	Confidence Interval	(2-Sided) 95%; -10.590 to -3.829
	Parameter Dispersion	Type: Value:
	Estimation Comments	Because Bayesian analyses were employed, a 95% two-sided credible interval was used instead of a confidence interval. This reflects the 2.5th and 97.5th percentile of possible values for the BiV-RV difference in mean LVESVI change through 12 months.

22. Secondary Outcome

Title	Change in Left Ventricular End Systolic Volume Index (LVESVI) From Randomization to 18 Months
Description	The endpoint will be a subject's change in Left Ventricular End Systolic Volume Index (a measure of the volume of blood in the left ventricle at the end of systole, normalized over body surface area). In other words, a measure of the size of the left ventricle. For each subject the measure is the 18 month - randomization visit difference in LVESVI. Negative values correspond to reductions in LVESVI over time.
Time Frame	Randomization to 18 Months

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Biventricular Pacing Arm	Right Ventricular Pacing Arm
Arm/Group Description	Subjects randomized to receive biventricular pacing	Subjects randomized to receive right ventricular pacing.
Measure Participants	219	225
Mean (Standard Deviation) [ml/square meter of body surface area]	-8.8 (18.9)	-0.5 (19.9)

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Biventricular Pacing Arm, Right Ventricular Pacing Arm
	Comments	The null hypothesis is that patients with AV block, ejection fractions of at most 50%, and NYHA classifications of I, II, or III who receive biventricular pacing have the same average change in LVESVI from randomization to 18 months as corresponding patients who receive right ventricular pacing. This was tested against the hypothesis that patients with biventricular pacing have a different change in LVESVI from randomization to 18 months than patients with right ventricular pacing.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value
	Comments
	Method
	Comments
Method of Estimation	Estimation Parameter	Posterior BiV - RV Mean Difference
	Estimated Value	-8.242
	Confidence Interval	(2-Sided) 95%; -11.860 to -4.574
	Parameter Dispersion	Type: Value:
	Estimation Comments	Because Bayesian analyses were employed, a 95% two-sided credible interval was used instead of a confidence interval. This reflects the 2.5th and 97.5th percentile of possible values for the BiV-RV difference in mean LVESVI change through 18 months.

23. Secondary Outcome

Title	Change in Left Ventricular End Systolic Volume Index (LVESVI) From Randomization to 24 Months
Description	The endpoint will be a subject's change in Left Ventricular End Systolic Volume Index (a measure of the volume of blood in the left ventricle at the end of systole, normalized over body surface area). In other words, a measure of the size of the left ventricle. For each subject the measure is the 24 month - randomization visit difference in LVESVI. Negative values correspond to reductions in LVESVI over time.
Time Frame	Randomization to 24 Months

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Biventricular Pacing Arm	Right Ventricular Pacing Arm
Arm/Group Description	Subjects randomized to receive biventricular pacing	Subjects randomized to receive right ventricular pacing.
Measure Participants	187	204
Mean (Standard Deviation) [ml/square meter of body surface area]	-6.0 (22.6)	1.4 (21.3)

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Biventricular Pacing Arm, Right Ventricular Pacing Arm
	Comments	The null hypothesis is that patients with AV block, ejection fractions of at most 50%, and NYHA classifications of I, II, or III who receive biventricular pacing have the same average change in LVESVI from randomization to 24 months as corresponding patients who receive right ventricular pacing. This was tested against the hypothesis that patients with biventricular pacing have a different change in LVESVI from randomization to 24 months than patients with right ventricular pacing.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value
	Comments
	Method
	Comments
Method of Estimation	Estimation Parameter	Posterior BiV - RV Mean Difference
	Estimated Value	-7.268
	Confidence Interval	(2-Sided) 95%; -11.690 to -2.846
	Parameter Dispersion	Type: Value:
	Estimation Comments	Because Bayesian analyses were employed, a 95% two-sided credible interval was used instead of a confidence interval. This reflects the 2.5th and 97.5th percentile of possible values for the BiV-RV difference in mean LVESVI change through 24 months.

24. Secondary Outcome

Title	Change in Left Ventricular End Diastolic Volume Index (LVEDVI) From Randomization to 6 Months
Description	The endpoint will be a subject's change in Left Ventricular End Diastolic Volume Index (a measure of the volume of blood in the left ventricle at the end of diastole, normalized over body surface area). In other words, a measure of the size of the left ventricle. For each subject the measure is the 6 month - randomization visit difference in LVEDVI. Negative values correspond to reductions in LVEDVI over time.
Time Frame	Randomization to 6 Months

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Biventricular Pacing Arm	Right Ventricular Pacing Arm
Arm/Group Description	Subjects randomized to receive biventricular pacing	Subjects randomized to receive right ventricular pacing.
Measure Participants	281	273
Mean (Standard Deviation) [ml/square meter of body surface area]	-6.2 (19.2)	-0.3 (19.5)

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Biventricular Pacing Arm, Right Ventricular Pacing Arm
	Comments	The null hypothesis is that patients with AV block, ejection fractions of at most 50%, and NYHA classifications of I, II, or III who receive biventricular pacing have the same average change in LVEDVI from randomization to 6 months as corresponding patients who receive right ventricular pacing. This was tested against the hypothesis that patients with biventricular pacing have a different change in LVEDVI from randomization to 6 months than patients with right ventricular pacing.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value
	Comments
	Method
	Comments
Method of Estimation	Estimation Parameter	Posterior BiV - RV Mean Difference
	Estimated Value	-5.858
	Confidence Interval	(2-Sided) 95%; -9.085 to -2.562
	Parameter Dispersion	Type: Value:
	Estimation Comments	Because Bayesian analyses were employed, a 95% two-sided credible interval was used instead of a confidence interval. This reflects the 2.5th and 97.5th percentile of possible values for the BiV-RV difference in mean LVEDVI change through 6 months.

25. Secondary Outcome

Title	Change in Left Ventricular End Diastolic Volume Index (LVEDVI) From Randomization to 12 Months
Description	The endpoint will be a subject's change in Left Ventricular End Diastolic Volume Index (a measure of the volume of blood in the left ventricle at the end of diastole, normalized over body surface area). In other words, a measure of the size of the left ventricle. For each subject the measure is the 12 month - randomization visit difference in LVEDVI. Negative values correspond to reductions in LVEDVI over time.
Time Frame	Randomization to 12 Months

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Biventricular Pacing Arm	Right Ventricular Pacing Arm
Arm/Group Description	Subjects randomized to receive biventricular pacing	Subjects randomized to receive right ventricular pacing.
Measure Participants	261	256
Mean (Standard Deviation) [ml/square meter of body surface area]	-7.0 (20.6)	-1.1 (22.2)

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Biventricular Pacing Arm, Right Ventricular Pacing Arm
	Comments	The null hypothesis is that patients with AV block, ejection fractions of at most 50%, and NYHA classifications of I, II, or III who receive biventricular pacing have the same average change in LVEDVI from randomization to 12 months as corresponding patients who receive right ventricular pacing. This was tested against the hypothesis that patients with biventricular pacing have a different change in LVEDVI from randomization to 12 months than patients with right ventricular pacing.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value
	Comments
	Method
	Comments
Method of Estimation	Estimation Parameter	Posterior BiV - RV Mean Difference
	Estimated Value	-5.807
	Confidence Interval	(2-Sided) 95%; -9.467 to -2.038
	Parameter Dispersion	Type: Value:
	Estimation Comments	Because Bayesian analyses were employed, a 95% two-sided credible interval was used instead of a confidence interval. This reflects the 2.5th and 97.5th percentile of possible values for the BiV-RV difference in mean LVEDVI change through 12 months.

26. Secondary Outcome

Title	Change in Left Ventricular End Diastolic Volume Index (LVEDVI) From Randomization to 18 Months
Description	The endpoint will be a subject's change in Left Ventricular End Diastolic Volume Index (a measure of the volume of blood in the left ventricle at the end of diastole, normalized over body surface area). In other words, a measure of the size of the left ventricle. For each subject the measure is the 18 month - randomization visit difference in LVEDVI. Negative values correspond to reductions in LVEDVI over time.
Time Frame	Randomization to 18 Months

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Biventricular Pacing Arm	Right Ventricular Pacing Arm
Arm/Group Description	Subjects randomized to receive biventricular pacing	Subjects randomized to receive right ventricular pacing.
Measure Participants	220	225
Mean (Standard Deviation) [ml/square meter of body surface area]	-9.8 (21.4)	-0.8 (22.4)

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Biventricular Pacing Arm, Right Ventricular Pacing Arm
	Comments	The null hypothesis is that patients with AV block, ejection fractions of at most 50%, and NYHA classifications of I, II, or III who receive biventricular pacing have the same average change in LVEDVI from randomization to 18 months as corresponding patients who receive right ventricular pacing. This was tested against the hypothesis that patients with biventricular pacing have a different change in LVEDVI from randomization to 18 months than patients with right ventricular pacing.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value
	Comments
	Method
	Comments
Method of Estimation	Estimation Parameter	Posterior BiV - RV Mean Difference
	Estimated Value	-8.844
	Confidence Interval	(2-Sided) 95%; -12.910 to -4.681
	Parameter Dispersion	Type: Value:
	Estimation Comments	Because Bayesian analyses were employed, a 95% two-sided credible interval was used instead of a confidence interval. This reflects the 2.5th and 97.5th percentile of possible values for the BiV-RV difference in mean LVEDVI change through 18 months.

27. Secondary Outcome

Title	Change in Left Ventricular End Diastolic Volume Index (LVEDVI) From Randomization to 24 Months
Description	The endpoint will be a subject's change in Left Ventricular End Diastolic Volume Index (a measure of the volume of blood in the left ventricle at the end of diastole, normalized over body surface area). In other words, a measure of the size of the left ventricle. For each subject the measure is the 24 month - randomization visit difference in LVEDVI. Negative values correspond to reductions in LVEDVI over time.
Time Frame	Randomization to 24 Months

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Biventricular Pacing Arm	Right Ventricular Pacing Arm
Arm/Group Description	Subjects randomized to receive biventricular pacing	Subjects randomized to receive right ventricular pacing.
Measure Participants	189	206
Mean (Standard Deviation) [ml/square meter of body surface area]	-6.9 (24.9)	-0.1 (23.7)

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Biventricular Pacing Arm, Right Ventricular Pacing Arm
	Comments	The null hypothesis is that patients with AV block, ejection fractions of at most 50%, and NYHA classifications of I, II, or III who receive biventricular pacing have the same average change in LVEDVI from randomization to 24 months as corresponding patients who receive right ventricular pacing. This was tested against the hypothesis that patients with biventricular pacing have a different change in LVEDVI from randomization to 24 months than patients with right ventricular pacing.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value
	Comments
	Method
	Comments
Method of Estimation	Estimation Parameter	Posterior BiV - RV Mean Difference
	Estimated Value	-6.615
	Confidence Interval	(2-Sided) 95%; -11.370 to -1.736
	Parameter Dispersion	Type: Value:
	Estimation Comments	Because Bayesian analyses were employed, a 95% two-sided credible interval was used instead of a confidence interval. This reflects the 2.5th and 97.5th percentile of possible values for the BiV-RV difference in mean LVEDVI change through 24 months.

28. Secondary Outcome

Title	Change in Left Ventricular Mass (LV Mass) From Randomization to 6 Months
Description	The endpoint will be a subject's change in Left Ventricular Mass ( a measure of the size of the left ventricle) from randomization to 6 months. For each subject the measurement was calculated as 6 month - randomization visit difference in LV mass measurement. Negative values correspond to a reduction in LV mass over time.
Time Frame	Randomization to 6 Months

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Biventricular Pacing Arm	Right Ventricular Pacing Arm
Arm/Group Description	Subjects randomized to receive biventricular pacing	Subjects randomized to receive right ventricular pacing.
Measure Participants	220	208
Mean (Standard Deviation) [grams]	-8.4 (43.1)	-4.2 (47.5)

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Biventricular Pacing Arm, Right Ventricular Pacing Arm
	Comments	The null hypothesis is that patients with AV block, NYHA I-III, and LVEF of at most 50% who receive RV pacing have similar changes in LV Mass through 6 months compared to similar patients who receive BiV pacing. This was tested against the alternative hypothesis that patients have different changes in LV Mass through 6 months with BiV pacing than RV pacing. Change was calculated as 6 month value - randomization visit value.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value
	Comments
	Method
	Comments
Method of Estimation	Estimation Parameter	Posterior BiV - RV Mean Difference
	Estimated Value	-3.894
	Confidence Interval	(2-Sided) 95%; -12.130 to 3.953
	Parameter Dispersion	Type: Value:
	Estimation Comments	Because Bayesian analyses were employed, a 95% two-sided credible interval was used instead of a confidence interval. This reflects the 2.5th and 97.5th percentile of possible values for the BiV-RV difference in mean LV Mass change through 6 months.

29. Secondary Outcome

Title	Change in Left Ventricular Mass (LV Mass) From Randomization to 12 Months
Description	The endpoint will be a subject's change in Left Ventricular Mass ( a measure of the size of the left ventricle) from randomization to 12 months. For each subject the measurement was calculated as 12 month - randomization visit difference in LV mass measurement. Negative values correspond to a reduction in LV mass over time.
Time Frame	Randomization to 12 Months

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Biventricular Pacing Arm	Right Ventricular Pacing Arm
Arm/Group Description	Subjects randomized to receive biventricular pacing	Subjects randomized to receive right ventricular pacing.
Measure Participants	211	199
Mean (Standard Deviation) [grams]	-15.8 (46.8)	-4.7 (52.4)

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Biventricular Pacing Arm, Right Ventricular Pacing Arm
	Comments	The null hypothesis is that patients with AV block, NYHA I-III, and LVEF of at most 50% who receive RV pacing have similar changes in LV Mass through 12 months compared to similar patients who receive BiV pacing. This was tested against the alternative hypothesis that patients have different changes in LV Mass through 12 months with BiV pacing than RV pacing. Change was calculated as 12 month value - randomization visit value.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value
	Comments
	Method
	Comments
Method of Estimation	Estimation Parameter	Posterior BiV - RV Mean Difference
	Estimated Value	-10.160
	Confidence Interval	(2-Sided) 95%; -19.330 to -0.857
	Parameter Dispersion	Type: Value:
	Estimation Comments	Because Bayesian analyses were employed, a 95% two-sided credible interval was used instead of a confidence interval. This reflects the 2.5th and 97.5th percentile of possible values for the BiV-RV difference in mean LV Mass change through 12 months.

30. Secondary Outcome

Title	Change in Left Ventricular Mass (LV Mass) From Randomization to 18 Months
Description	The endpoint will be a subject's change in Left Ventricular Mass ( a measure of the size of the left ventricle) from randomization to 18 months. For each subject the measurement was calculated as 18 month - randomization visit difference in LV mass measurement. Negative values correspond to a reduction in LV mass over time.
Time Frame	Randomization to 18 Months

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Biventricular Pacing Arm	Right Ventricular Pacing Arm
Arm/Group Description	Subjects randomized to receive biventricular pacing	Subjects randomized to receive right ventricular pacing.
Measure Participants	168	176
Mean (Standard Deviation) [grams]	-16.8 (48.8)	-7.2 (49.8)

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Biventricular Pacing Arm, Right Ventricular Pacing Arm
	Comments	The null hypothesis is that patients with AV block, NYHA I-III, and LVEF of at most 50% who receive RV pacing have similar changes in LV Mass through 18 months compared to similar patients who receive BiV pacing. This was tested against the alternative hypothesis that patients have different changes in LV Mass through 18 months with BiV pacing than RV pacing. Change was calculated as 18 month value - randomization visit value.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value
	Comments
	Method
	Comments
Method of Estimation	Estimation Parameter	Posterior BiV - RV Mean Difference
	Estimated Value	-8.316
	Confidence Interval	(2-Sided) 95%; -18.190 to 1.623
	Parameter Dispersion	Type: Value:
	Estimation Comments	Because Bayesian analyses were employed, a 95% two-sided credible interval was used instead of a confidence interval. This reflects the 2.5th and 97.5th percentile of possible values for the BiV-RV difference in mean LV Mass change through 18 months.

31. Secondary Outcome

Title	Change in Left Ventricular Mass (LV Mass) From Randomization to 24 Months
Description	The endpoint will be a subject's change in Left Ventricular Mass ( a measure of the size of the left ventricle) from randomization to 24 months. For each subject the measurement was calculated as 24 month - randomization visit difference in LV mass measurement. Negative values correspond to a reduction in LV mass over time.
Time Frame	Randomization to 24 Months

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Biventricular Pacing Arm	Right Ventricular Pacing Arm
Arm/Group Description	Subjects randomized to receive biventricular pacing	Subjects randomized to receive right ventricular pacing.
Measure Participants	150	163
Mean (Standard Deviation) [grams]	-19.4 (45.1)	-6.8 (49.6)

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Biventricular Pacing Arm, Right Ventricular Pacing Arm
	Comments	The null hypothesis is that patients with AV block, NYHA I-III, and LVEF of at most 50% who receive RV pacing have similar changes in LV Mass through 24 months compared to similar patients who receive BiV pacing. This was tested against the alternative hypothesis that patients have different changes in LV Mass through 24 months with BiV pacing than RV pacing. Change was calculated as 24 month value - randomization visit value.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value
	Comments
	Method
	Comments
Method of Estimation	Estimation Parameter	Posterior BiV - RV Mean Difference
	Estimated Value	-11.080
	Confidence Interval	(2-Sided) 95%; -21.110 to -0.956
	Parameter Dispersion	Type: Value:
	Estimation Comments	Because Bayesian analyses were employed, a 95% two-sided credible interval was used instead of a confidence interval. This reflects the 2.5th and 97.5th percentile of possible values for the BiV-RV difference in mean LV Mass change through 24 months.

32. Secondary Outcome

Title	Change in Left Ventricular End Diastolic Dimension (LVEDD) From Randomization to 6 Months
Description	The endpoint will be a subject's change in LVEDD (a measure of the dimension of the left ventricle at the end of diastole). For each subject the measure was the 6 month - randomization visit difference in LVEDD value. Negative values correspond to reductions in LVEDD.
Time Frame	Randomization to 6 Months

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Biventricular Pacing Arm	Right Ventricular Pacing Arm
Arm/Group Description	Subjects randomized to receive biventricular pacing	Subjects randomized to receive right ventricular pacing.
Measure Participants	254	242
Mean (Standard Deviation) [cm]	-0.1 (0.6)	0.0 (0.6)

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Biventricular Pacing Arm, Right Ventricular Pacing Arm
	Comments	The null hypothesis is that patients with AV block, ejection fractions of at most 50%, and NYHA classifications of I, II, or III who receive biventricular pacing have the same average change in LVEDD from randomization to 6 months as similar patients who receive right ventricular pacing. This was tested against the hypothesis that patients with BiV pacing have a different change in LVEDD from randomization to 6 months than patients with RV pacing. Negative values reflect reductions in LVEDD.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value
	Comments
	Method
	Comments
Method of Estimation	Estimation Parameter	Posterior BiV - RV Mean Difference
	Estimated Value	-0.126
	Confidence Interval	(2-Sided) 95%; -0.235 to -0.014
	Parameter Dispersion	Type: Value:
	Estimation Comments	Because Bayesian analyses were employed, a 95% two-sided credible interval was used instead of a confidence interval. This reflects the 2.5th and 97.5th percentile of possible values for the BiV-RV difference in mean LVEDD change through 6 months.

33. Secondary Outcome

Title	Change in Left Ventricular End Diastolic Dimension (LVEDD) From Randomization to 12 Months
Description	The endpoint will be a subject's change in LVEDD (a measure of the dimension of the left ventricle at the end of diastole). For each subject the measure was the 12 month - randomization visit difference in LVEDD value. Negative values correspond to reductions in LVEDD.
Time Frame	Randomization to 12 Months

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Biventricular Pacing Arm	Right Ventricular Pacing Arm
Arm/Group Description	Subjects randomized to receive biventricular pacing	Subjects randomized to receive right ventricular pacing.
Measure Participants	241	232
Mean (Standard Deviation) [cm]	-0.1 (0.7)	0.0 (0.7)

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Biventricular Pacing Arm, Right Ventricular Pacing Arm
	Comments	The null hypothesis is that patients with AV block, ejection fractions of at most 50%, and NYHA classifications of I, II, or III who receive biventricular pacing have the same average change in LVEDD from randomization to 12 months as similar patients who receive right ventricular pacing. This was tested against the hypothesis that patients with BiV pacing have a different change in LVEDD from randomization to 12 months than patients with RV pacing. Negative values reflect reductions in LVEDD.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value
	Comments
	Method
	Comments
Method of Estimation	Estimation Parameter	Posterior BiV - RV Mean Difference
	Estimated Value	-0.162
	Confidence Interval	(2-Sided) 95%; -0.287 to -0.035
	Parameter Dispersion	Type: Value:
	Estimation Comments	Because Bayesian analyses were employed, a 95% two-sided credible interval was used instead of a confidence interval. This reflects the 2.5th and 97.5th percentile of possible values for the BiV-RV difference in mean LVEDD change through 12 months.

34. Secondary Outcome

Title	Change in Left Ventricular End Diastolic Dimension (LVEDD) From Randomization to 18 Months
Description	The endpoint will be a subject's change in LVEDD (a measure of the dimension of the left ventricle at the end of diastole). For each subject the measure was the 18 month - randomization visit difference in LVEDD value. Negative values correspond to reductions in LVEDD.
Time Frame	Randomization to 18 Months

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Biventricular Pacing Arm	Right Ventricular Pacing Arm
Arm/Group Description	Subjects randomized to receive biventricular pacing	Subjects randomized to receive right ventricular pacing.
Measure Participants	201	204
Mean (Standard Deviation) [cm]	-0.2 (0.6)	0.0 (0.7)

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Biventricular Pacing Arm, Right Ventricular Pacing Arm
	Comments	The null hypothesis is that patients with AV block, ejection fractions of at most 50%, and NYHA classifications of I, II, or III who receive biventricular pacing have the same average change in LVEDD from randomization to 18 months as similar patients who receive right ventricular pacing. This was tested against the hypothesis that patients with BiV pacing have a different change in LVEDD from randomization to 18 months than patients with RV pacing. Negative values reflect reductions in LVEDD.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value
	Comments
	Method
	Comments
Method of Estimation	Estimation Parameter	Posterior BiV - RV Mean Difference
	Estimated Value	-0.163
	Confidence Interval	(2-Sided) 95%; -0.293 to -0.030
	Parameter Dispersion	Type: Value:
	Estimation Comments	Because Bayesian analyses were employed, a 95% two-sided credible interval was used instead of a confidence interval. This reflects the 2.5th and 97.5th percentile of possible values for the BiV-RV difference in mean LVEDD change through 18 months.

35. Secondary Outcome

Title	Change in Left Ventricular End Diastolic Dimension (LVEDD) From Randomization to 24 Months
Description	The endpoint will be a subject's change in LVEDD (a measure of the dimension of the left ventricle at the end of diastole). For each subject the measure was the 24 month - randomization visit difference in LVEDD value. Negative values correspond to reductions in LVEDD.
Time Frame	Randomization to 24 Months

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Biventricular Pacing Arm	Right Ventricular Pacing Arm
Arm/Group Description	Subjects randomized to receive biventricular pacing	Subjects randomized to receive right ventricular pacing.
Measure Participants	175	186
Mean (Standard Deviation) [cm]	-0.3 (0.7)	0.0 (0.7)

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Biventricular Pacing Arm, Right Ventricular Pacing Arm
	Comments	The null hypothesis is that patients with AV block, ejection fractions of at most 50%, and NYHA classifications of I, II, or III who receive biventricular pacing have the same average change in LVEDD from randomization to 24 months as similar patients who receive right ventricular pacing. This was tested against the hypothesis that patients with BiV pacing have a different change in LVEDD from randomization to 24 months than patients with RV pacing. Negative values reflect reductions in LVEDD.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value
	Comments
	Method
	Comments
Method of Estimation	Estimation Parameter	Posterior BiV - RV Mean Difference
	Estimated Value	-0.245
	Confidence Interval	(2-Sided) 95%; -0.390 to -0.097
	Parameter Dispersion	Type: Value:
	Estimation Comments	Because Bayesian analyses were employed, a 95% two-sided credible interval was used instead of a confidence interval. This reflects the 2.5th and 97.5th percentile of possible values for the BiV-RV difference in mean LVEDD change through 24 months.

36. Secondary Outcome

Title	Change in Left Ventricular End Systolic Dimension (LVESD) From Randomization to 6 Months
Description	The endpoint will be a subject's change in LVESD (a measure of the dimension of the left ventricle at the end of systole). For each subject the measure was the 6 month - randomization visit difference in LVESD value. Negative values correspond to reductions in LVESD.
Time Frame	Randomization to 6 Months

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Biventricular Pacing Arm	Right Ventricular Pacing Arm
Arm/Group Description	Subjects randomized to receive biventricular pacing	Subjects randomized to receive right ventricular pacing.
Measure Participants	250	241
Mean (Standard Deviation) [cm]	-0.1 (0.6)	0.0 (0.7)

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Biventricular Pacing Arm, Right Ventricular Pacing Arm
	Comments	The null hypothesis is that patients with AV block, ejection fractions of at most 50%, and NYHA classifications of I, II, or III who receive biventricular pacing have the same average change in LVESD from randomization to 6 months as similar patients who receive right ventricular pacing. This was tested against the hypothesis that patients with BiV pacing have a different change in LVESD from randomization to 6 months than patients with RV pacing. Negative values reflect reductions in LVESD.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value
	Comments
	Method
	Comments
Method of Estimation	Estimation Parameter	Posterior BiV - RV Mean Difference
	Estimated Value	-0.066
	Confidence Interval	(2-Sided) 95%; -0.185 to 0.055
	Parameter Dispersion	Type: Value:
	Estimation Comments	Because Bayesian analyses were employed, a 95% two-sided credible interval was used instead of a confidence interval. This reflects the 2.5th and 97.5th percentile of possible values for the BiV-RV difference in mean LVESD change through 6 months.

37. Secondary Outcome

Title	Change in Left Ventricular End Systolic Dimension (LVESD) From Randomization to 12 Months
Description	The endpoint will be a subject's change in LVESD (a measure of the dimension of the left ventricle at the end of systole). For each subject the measure was the 12 month - randomization visit difference in LVESD value. Negative values correspond to reductions in LVESD.
Time Frame	Randomization to 12 Months

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Biventricular Pacing Arm	Right Ventricular Pacing Arm
Arm/Group Description	Subjects randomized to receive biventricular pacing	Subjects randomized to receive right ventricular pacing.
Measure Participants	239	231
Mean (Standard Deviation) [cm]	0.0 (0.7)	0.1 (0.7)

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Biventricular Pacing Arm, Right Ventricular Pacing Arm
	Comments	The null hypothesis is that patients with AV block, ejection fractions of at most 50%, and NYHA classifications of I, II, or III who receive biventricular pacing have the same average change in LVESD from randomization to 12 months as similar patients who receive right ventricular pacing. This was tested against the hypothesis that patients with BiV pacing have a different change in LVESD from randomization to 12 months than patients with RV pacing. Negative values reflect reductions in LVESD.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value
	Comments
	Method
	Comments
Method of Estimation	Estimation Parameter	Posterior BiV - RV Mean Difference
	Estimated Value	-0.104
	Confidence Interval	(2-Sided) 95%; -0.236 to 0.029
	Parameter Dispersion	Type: Value:
	Estimation Comments	Because Bayesian analyses were employed, a 95% two-sided credible interval was used instead of a confidence interval. This reflects the 2.5th and 97.5th percentile of possible values for the BiV-RV difference in mean LVESD change through 12 months.

38. Secondary Outcome

Title	Change in Left Ventricular End Systolic Dimension (LVESD) From Randomization to 18 Months
Description	The endpoint will be a subject's change in LVESD (a measure of the dimension of the left ventricle at the end of systole). For each subject the measure was the 18 month - randomization visit difference in LVESD value. Negative values correspond to reductions in LVESD.
Time Frame	Randomization to 18 Months

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Biventricular Pacing Arm	Right Ventricular Pacing Arm
Arm/Group Description	Subjects randomized to receive biventricular pacing	Subjects randomized to receive right ventricular pacing.
Measure Participants	199	204
Mean (Standard Deviation) [cm]	-0.1 (0.7)	0.0 (0.7)

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Biventricular Pacing Arm, Right Ventricular Pacing Arm
	Comments	The null hypothesis is that patients with AV block, ejection fractions of at most 50%, and NYHA classifications of I, II, or III who receive biventricular pacing have the same average change in LVESD from randomization to 18 months as similar patients who receive right ventricular pacing. This was tested against the hypothesis that patients with BiV pacing have a different change in LVESD from randomization to 18 months than patients with RV pacing. Negative values reflect reductions in LVESD.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value
	Comments
	Method
	Comments
Method of Estimation	Estimation Parameter	Posterior BiV - RV Mean Difference
	Estimated Value	-0.060
	Confidence Interval	(2-Sided) 95%; -0.204 to 0.087
	Parameter Dispersion	Type: Value:
	Estimation Comments	Because Bayesian analyses were employed, a 95% two-sided credible interval was used instead of a confidence interval. This reflects the 2.5th and 97.5th percentile of possible values for the BiV-RV difference in mean LVESD change through 18 months.

39. Secondary Outcome

Title	Change in Left Ventricular End Systolic Dimension (LVESD) From Randomization to 24 Months
Description	The endpoint will be a subject's change in LVESD (a measure of the dimension of the left ventricle at the end of systole). For each subject the measure was the 24 month - randomization visit difference in LVESD value. Negative values correspond to reductions in LVESD.
Time Frame	Randomization to 24 Months

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Biventricular Pacing Arm	Right Ventricular Pacing Arm
Arm/Group Description	Subjects randomized to receive biventricular pacing	Subjects randomized to receive right ventricular pacing.
Measure Participants	173	185
Mean (Standard Deviation) [cm]	-0.1 (0.8)	0.1 (0.7)

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Biventricular Pacing Arm, Right Ventricular Pacing Arm
	Comments	The null hypothesis is that patients with AV block, ejection fractions of at most 50%, and NYHA classifications of I, II, or III who receive biventricular pacing have the same average change in LVESD from randomization to 24 months as similar patients who receive right ventricular pacing. This was tested against the hypothesis that patients with BiV pacing have a different change in LVESD from randomization to 24 months than patients with RV pacing. Negative values reflect reductions in LVESD.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value
	Comments
	Method
	Comments
Method of Estimation	Estimation Parameter	Posterior BiV - RV Mean Difference
	Estimated Value	-0.180
	Confidence Interval	(2-Sided) 95%; -0.339 to -0.018
	Parameter Dispersion	Type: Value:
	Estimation Comments	Because Bayesian analyses were employed, a 95% two-sided credible interval was used instead of a confidence interval. This reflects the 2.5th and 97.5th percentile of possible values for the BiV-RV difference in mean LVESD change through 24 months.

40. Secondary Outcome

Title	Change in Mitral Regurgitation From Randomization to 6 Months
Description	The endpoint will be a subject's change in mitral regurgitation (a measure of how much blood flows backwards into the heart due to the mitral valve not closing properly). The measure for each subject will be the 6 month - randomization visit difference in mitral regurgitation. Negative values reflect reductions in mitral regurgitation over time.
Time Frame	Randomization to 6 Months

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Biventricular Pacing Arm	Right Ventricular Pacing Arm
Arm/Group Description	Subjects randomized to receive biventricular pacing	Subjects randomized to receive right ventricular pacing.
Measure Participants	247	225
Mean (Standard Deviation) [percentage of left atrial area]	-1.3 (12.4)	-0.6 (11.2)

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Biventricular Pacing Arm, Right Ventricular Pacing Arm
	Comments	The null hypothesis is that patients with AV block, NYHA I-III, and LVEF of at most 50% who receive RV pacing have similar changes in Mitral Regurgitation (MR) through 6 months compared to similar patients who receive BiV pacing. This was tested against the alternative hypothesis that patients have different changes in Mitral Regurgitation through 6 months with BiV pacing than RV pacing. Change was calculated as 6 month value - randomization visit value.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value
	Comments
	Method
	Comments
Method of Estimation	Estimation Parameter	Posterior BiV - RV Mean Difference
	Estimated Value	-0.683
	Confidence Interval	(2-Sided) 95%; -2.828 to 1.506
	Parameter Dispersion	Type: Value:
	Estimation Comments	Because Bayesian analyses were employed, a 95% two-sided credible interval was used instead of a confidence interval. This reflects the 2.5th and 97.5th percentile of possible values for the BiV-RV difference in mean MR change through 6 months.

41. Secondary Outcome

Title	Change in Mitral Regurgitation From Randomization to 12 Months
Description	The endpoint will be a subject's change in mitral regurgitation (a measure of how much blood flows backwards into the heart due to the mitral valve not closing properly). The measure for each subject will be the 12 month - randomization visit difference in mitral regurgitation. Negative values reflect reductions in mitral regurgitation over time.
Time Frame	Randomization to 12 Months

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Biventricular Pacing Arm	Right Ventricular Pacing Arm
Arm/Group Description	Subjects randomized to receive biventricular pacing	Subjects randomized to receive right ventricular pacing.
Measure Participants	235	214
Mean (Standard Deviation) [percentage of left atrial area]	-1.3 (12.0)	-0.8 (12.6)

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Biventricular Pacing Arm, Right Ventricular Pacing Arm
	Comments	The null hypothesis is that patients with AV block, NYHA I-III, and LVEF of at most 50% who receive RV pacing have similar changes in Mitral Regurgitation (MR) through 12 months compared to similar patients who receive BiV pacing. This was tested against the alternative hypothesis that patients have different changes in Mitral Regurgitation through 12 months with BiV pacing than RV pacing. Change was calculated as 12 month value - randomization visit value.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value
	Comments
	Method
	Comments
Method of Estimation	Estimation Parameter	Posterior BiV - RV Mean Difference
	Estimated Value	-0.564
	Confidence Interval	(2-Sided) 95%; -2.843 to 1.773
	Parameter Dispersion	Type: Value:
	Estimation Comments	Because Bayesian analyses were employed, a 95% two-sided credible interval was used instead of a confidence interval. This reflects the 2.5th and 97.5th percentile of possible values for the BiV-RV difference in mean MR change through 12 months.

42. Secondary Outcome

Title	Change in Mitral Regurgitation From Randomization to 18 Months
Description	The endpoint will be a subject's change in mitral regurgitation (a measure of how much blood flows backwards into the heart due to the mitral valve not closing properly). The measure for each subject will be the 18 month - randomization visit difference in mitral regurgitation. Negative values reflect reductions in mitral regurgitation over time.
Time Frame	Randomization to 18 Months

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Biventricular Pacing Arm	Right Ventricular Pacing Arm
Arm/Group Description	Subjects randomized to receive biventricular pacing	Subjects randomized to receive right ventricular pacing.
Measure Participants	188	195
Mean (Standard Deviation) [percentage of left atrial area]	-1.9 (12.1)	-1.9 (11.5)

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Biventricular Pacing Arm, Right Ventricular Pacing Arm
	Comments	The null hypothesis is that patients with AV block, NYHA I-III, and LVEF of at most 50% who receive RV pacing have similar changes in Mitral Regurgitation (MR) through 18 months compared to similar patients who receive BiV pacing. This was tested against the alternative hypothesis that patients have different changes in Mitral Regurgitation through 18 months with BiV pacing than RV pacing. Change was calculated as 18 month value - randomization visit value.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value
	Comments
	Method
	Comments
Method of Estimation	Estimation Parameter	Posterior BiV - RV Mean Difference
	Estimated Value	0.016
	Confidence Interval	(2-Sided) 95%; -2.379 to 2.425
	Parameter Dispersion	Type: Value:
	Estimation Comments	Because Bayesian analyses were employed, a 95% two-sided credible interval was used instead of a confidence interval. This reflects the 2.5th and 97.5th percentile of possible values for the BiV-RV difference in mean MR change through 18 months.

43. Secondary Outcome

Title	Change in Mitral Regurgitation From Randomization to 24 Months
Description	The endpoint will be a subject's change in mitral regurgitation (a measure of how much blood flows backwards into the heart due to the mitral valve not closing properly). The measure for each subject will be the 24 month - randomization visit difference in mitral regurgitation. Negative values reflect reductions in mitral regurgitation over time.
Time Frame	Randomization to 24 Months

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Biventricular Pacing Arm	Right Ventricular Pacing Arm
Arm/Group Description	Subjects randomized to receive biventricular pacing	Subjects randomized to receive right ventricular pacing.
Measure Participants	173	173
Mean (Standard Deviation) [percentage of left atrial area]	-1.1 (13.6)	-0.5 (11.4)

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Biventricular Pacing Arm, Right Ventricular Pacing Arm
	Comments	The null hypothesis is that patients with AV block, NYHA I-III, and LVEF of at most 50% who receive RV pacing have similar changes in Mitral Regurgitation (MR) through 24 months compared to similar patients who receive BiV pacing. This was tested against the alternative hypothesis that patients have different changes in Mitral Regurgitation through 24 months with BiV pacing than RV pacing. Change was calculated as 24 month value - randomization visit value.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value
	Comments
	Method
	Comments
Method of Estimation	Estimation Parameter	Posterior BiV - RV Mean Difference
	Estimated Value	-0.653
	Confidence Interval	(2-Sided) 95%; -3.337 to 2.046
	Parameter Dispersion	Type: Value:
	Estimation Comments	Because Bayesian analyses were employed, a 95% two-sided credible interval was used instead of a confidence interval. This reflects the 2.5th and 97.5th percentile of possible values for the BiV-RV difference in mean MR change through 24 months.

44. Secondary Outcome

Title	Change in Cardiac Index From Randomization to 6 Months
Description	The endpoint will be a subject's change in cardiac index (a measure of how much blood the left ventricle ejects in one minute, normalized over body surface area) from randomization to 6 months. The measure for each subject will be the 6 month - randomization visit value.
Time Frame	Randomization to 6 Months

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Biventricular Pacing Arm	Right Ventricular Pacing Arm
Arm/Group Description	Subjects randomized to receive biventricular pacing	Subjects randomized to receive right ventricular pacing.
Measure Participants	275	268
Mean (Standard Deviation) [liters per minute per squared meter]	0 (0.6)	-0.1 (0.7)

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Biventricular Pacing Arm, Right Ventricular Pacing Arm
	Comments	The null hypothesis is that patients with AV block, NYHA I-III, and LVEF of at most 50% who receive RV pacing have similar changes in Cardiac Index (CI) through 6 months compared to similar patients who receive BiV pacing. This was tested against the alternative hypothesis that patients have different changes in Cardiac Index through 6 months with BiV pacing than RV pacing. Change was calculated as 6 month value - randomization visit value.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value
	Comments
	Method
	Comments
Method of Estimation	Estimation Parameter	Posterior BiV - RV Mean Difference
	Estimated Value	0.080
	Confidence Interval	(2-Sided) 95%; -0.031 to 0.195
	Parameter Dispersion	Type: Value:
	Estimation Comments	Because Bayesian analyses were employed, a 95% two-sided credible interval was used instead of a confidence interval. This reflects the 2.5th and 97.5th percentile of possible values for the BiV-RV difference in mean CI change through 6 months.

45. Secondary Outcome

Title	Change in Cardiac Index From Randomization to 12 Months
Description	The endpoint will be a subject's change in cardiac index (a measure of how much blood the left ventricle ejects in one minute, normalized over body surface area) from randomization to 12 months. The measure for each subject will be the 12 month - randomization visit value.
Time Frame	Randomization to 12 Months

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Biventricular Pacing Arm	Right Ventricular Pacing Arm
Arm/Group Description	Subjects randomized to receive biventricular pacing	Subjects randomized to receive right ventricular pacing.
Measure Participants	257	250
Mean (Standard Deviation) [liters per minute per squared meter]	-0.1 (0.6)	-0.2 (0.6)

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Biventricular Pacing Arm, Right Ventricular Pacing Arm
	Comments	The null hypothesis is that patients with AV block, NYHA I-III, and LVEF of at most 50% who receive RV pacing have similar changes in Cardiac Index (CI) through 12 months compared to similar patients who receive BiV pacing. This was tested against the alternative hypothesis that patients have different changes in Cardiac Index through 12 months with BiV pacing than RV pacing. Change was calculated as 12 month value - randomization visit value.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value
	Comments
	Method
	Comments
Method of Estimation	Estimation Parameter	Posterior BiV - RV Mean Difference
	Estimated Value	0.086
	Confidence Interval	(2-Sided) 95%; -0.022 to 0.198
	Parameter Dispersion	Type: Value:
	Estimation Comments	Because Bayesian analyses were employed, a 95% two-sided credible interval was used instead of a confidence interval. This reflects the 2.5th and 97.5th percentile of possible values for the BiV-RV difference in mean CI change through 12 months.

46. Secondary Outcome

Title	Change in Cardiac Index From Randomization to 18 Months
Description	The endpoint will be a subject's change in cardiac index (a measure of how much blood the left ventricle ejects in one minute, normalized over body surface area) from randomization to 18 months. The measure for each subject will be the 18 month - randomization visit value.
Time Frame	Randomization to 18 Months

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Biventricular Pacing Arm	Right Ventricular Pacing Arm
Arm/Group Description	Subjects randomized to receive biventricular pacing	Subjects randomized to receive right ventricular pacing.
Measure Participants	215	218
Mean (Standard Deviation) [liters per minute per squared meter]	-0.1 (0.7)	0 (0.7)

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Biventricular Pacing Arm, Right Ventricular Pacing Arm
	Comments	The null hypothesis is that patients with AV block, NYHA I-III, and LVEF of at most 50% who receive RV pacing have similar changes in Cardiac Index (CI) through 18 months compared to similar patients who receive BiV pacing. This was tested against the alternative hypothesis that patients have different changes in Cardiac Index through 18 months with BiV pacing than RV pacing. Change was calculated as 18 month value - randomization visit value.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value
	Comments
	Method
	Comments
Method of Estimation	Estimation Parameter	Posterior BiV - RV Mean Difference
	Estimated Value	-0.081
	Confidence Interval	(2-Sided) 95%; -0.218 to 0.058
	Parameter Dispersion	Type: Value:
	Estimation Comments	Because Bayesian analyses were employed, a 95% two-sided credible interval was used instead of a confidence interval. This reflects the 2.5th and 97.5th percentile of possible values for the BiV-RV difference in mean CI change through 18 months.

47. Secondary Outcome

Title	Change in Cardiac Index From Randomization to 24 Months
Description	The endpoint will be a subject's change in cardiac index (a measure of how much blood the left ventricle ejects in one minute, normalized over body surface area) from randomization to 24 months. The measure for each subject will be the 24 month - randomization visit value.
Time Frame	Randomization to 24 Months

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Biventricular Pacing Arm	Right Ventricular Pacing Arm
Arm/Group Description	Subjects randomized to receive biventricular pacing	Subjects randomized to receive right ventricular pacing.
Measure Participants	186	198
Mean (Standard Deviation) [liters per minute per squared meter]	-0.1 (0.7)	-0.2 (0.7)

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Biventricular Pacing Arm, Right Ventricular Pacing Arm
	Comments	The null hypothesis is that patients with AV block, NYHA I-III, and LVEF of at most 50% who receive RV pacing have similar changes in Cardiac Index (CI) through 24 months compared to similar patients who receive BiV pacing. This was tested against the alternative hypothesis that patients have different changes in Cardiac Index through 24 months with BiV pacing than RV pacing. Change was calculated as 24 month value - randomization visit value.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value
	Comments
	Method
	Comments
Method of Estimation	Estimation Parameter	Posterior BiV - RV Mean Difference
	Estimated Value	0.047
	Confidence Interval	(2-Sided) 95%; -0.095 to 0.192
	Parameter Dispersion	Type: Value:
	Estimation Comments	Because Bayesian analyses were employed, a 95% two-sided credible interval was used instead of a confidence interval. This reflects the 2.5th and 97.5th percentile of possible values for the BiV-RV difference in mean CI change through 24 months.

48. Secondary Outcome

Title	Change in Interventricular Mechanical Delay (IVMD) From Randomization to 6 Months
Description	The endpoint will be a subject's change in interventricular mechanical delay (a measure of dyssynchrony between ventricles, measured in ms) from randomization to the 6 month visit. The measure will be the 6 month - randomization visit difference in IVMD.
Time Frame	Randomization to 6 Months

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Biventricular Pacing Arm	Right Ventricular Pacing Arm
Arm/Group Description	Subjects randomized to receive biventricular pacing	Subjects randomized to receive right ventricular pacing.
Measure Participants	220	208
Mean (Standard Deviation) [ms]	49.9 (134.2)	-4.2 (136.1)

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Biventricular Pacing Arm, Right Ventricular Pacing Arm
	Comments	The null hypothesis is that patients with AV block, NYHA I-III, and LVEF of at most 50% who receive RV pacing have similar changes in IVMD through 6 months compared to similar patients who receive BiV pacing. This was tested against the alternative hypothesis that patients have different changes in IVMD through 6 months with BiV pacing than RV pacing. Change was calculated as 6 month value - randomization visit value. A positive value reflected reduction in IVMD.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value
	Comments
	Method
	Comments
Method of Estimation	Estimation Parameter	Posterior BiV - RV Mean Difference
	Estimated Value	29.300
	Confidence Interval	(2-Sided) 95%; 10.040 to 48.640
	Parameter Dispersion	Type: Value:
	Estimation Comments	Because Bayesian analyses were employed, a 95% two-sided credible interval was used instead of a confidence interval. This reflects the 2.5th and 97.5th percentile of possible values for the BiV-RV difference in mean IVMD change through 6 months.

49. Secondary Outcome

Title	Change in Interventricular Mechanical Delay (IVMD) From Randomization to 12 Months
Description	The endpoint will be a subject's change in interventricular mechanical delay (a measure of dyssynchrony between ventricles, measured in ms) from randomization to the 12 month visit. The measure will be the 12 month - randomization visit difference in IVMD.
Time Frame	Randomization to 12 Months

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Biventricular Pacing Arm	Right Ventricular Pacing Arm
Arm/Group Description	Subjects randomized to receive biventricular pacing	Subjects randomized to receive right ventricular pacing.
Measure Participants	202	198
Mean (Standard Deviation) [ms]	38.5 (121.9)	0.4 (128.9)

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Biventricular Pacing Arm, Right Ventricular Pacing Arm
	Comments	The null hypothesis is that patients with AV block, NYHA I-III, and LVEF of at most 50% who receive RV pacing have similar changes in IVMD through 6 months compared to similar patients who receive BiV pacing. This was tested against the alternative hypothesis that patients have different changes in IVMD through 12 months with BiV pacing than RV pacing. Change was calculated as 12 month value - randomization visit value. A positive value reflected reduction in IVMD.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value
	Comments
	Method
	Comments
Method of Estimation	Estimation Parameter	Posterior BiV - RV Mean Difference
	Estimated Value	21.830
	Confidence Interval	(2-Sided) 95%; 2.841 to 40.870
	Parameter Dispersion	Type: Value:
	Estimation Comments	Because Bayesian analyses were employed, a 95% two-sided credible interval was used instead of a confidence interval. This reflects the 2.5th and 97.5th percentile of possible values for the BiV-RV difference in mean IVMD change through 12 months.

50. Secondary Outcome

Title	Change in Interventricular Mechanical Delay (IVMD) From Randomization to 18 Months
Description	The endpoint will be a subject's change in interventricular mechanical delay (a measure of dyssynchrony between ventricles, measured in ms) from randomization to the 18 month visit. The measure will be the 18 month - randomization visit difference in IVMD.
Time Frame	Randomization to 18 Months

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Biventricular Pacing Arm	Right Ventricular Pacing Arm
Arm/Group Description	Subjects randomized to receive biventricular pacing	Subjects randomized to receive right ventricular pacing.
Measure Participants	173	172
Mean (Standard Deviation) [ms]	55.1 (135.7)	-0.8 (136.7)

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Biventricular Pacing Arm, Right Ventricular Pacing Arm
	Comments	The null hypothesis is that patients with AV block, NYHA I-III, and LVEF of at most 50% who receive RV pacing have similar changes in IVMD through 6 months compared to similar patients who receive BiV pacing. This was tested against the alternative hypothesis that patients have different changes in IVMD through 18 months with BiV pacing than RV pacing. Change was calculated as 18 month value - randomization visit value. A positive value reflected reduction in IVMD.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value
	Comments
	Method
	Comments
Method of Estimation	Estimation Parameter	Posterior BiV - RV Mean Difference
	Estimated Value	26.530
	Confidence Interval	(2-Sided) 95%; 6.247 to 47.190
	Parameter Dispersion	Type: Value:
	Estimation Comments	Because Bayesian analyses were employed, a 95% two-sided credible interval was used instead of a confidence interval. This reflects the 2.5th and 97.5th percentile of possible values for the BiV-RV difference in mean IVMD change through 18 months.

51. Secondary Outcome

Title	Change in Interventricular Mechanical Delay (IVMD) From Randomization to 24 Months
Description	The endpoint will be a subject's change in interventricular mechanical delay (a measure of dyssynchrony between ventricles, measured in ms) from randomization to the 24 month visit. The measure will be the 24 month - randomization visit difference in IVMD.
Time Frame	Randomization to 24 Months

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Biventricular Pacing Arm	Right Ventricular Pacing Arm
Arm/Group Description	Subjects randomized to receive biventricular pacing	Subjects randomized to receive right ventricular pacing.
Measure Participants	150	160
Mean (Standard Deviation) [ms]	48.6 (138.1)	-4.9 (133.3)

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Biventricular Pacing Arm, Right Ventricular Pacing Arm
	Comments	The null hypothesis is that patients with AV block, NYHA I-III, and LVEF of at most 50% who receive RV pacing have similar changes in IVMD through 6 months compared to similar patients who receive BiV pacing. This was tested against the alternative hypothesis that patients have different changes in IVMD through 24 months with BiV pacing than RV pacing. Change was calculated as 24 month value - randomization visit value. A positive value reflected reduction in IVMD.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value
	Comments
	Method
	Comments
Method of Estimation	Estimation Parameter	Posterior BiV - RV Mean Difference
	Estimated Value	23.32
	Confidence Interval	(2-Sided) 95%; 1.999 to 44.530
	Parameter Dispersion	Type: Value:
	Estimation Comments	Because Bayesian analyses were employed, a 95% two-sided credible interval was used instead of a confidence interval. This reflects the 2.5th and 97.5th percentile of possible values for the BiV-RV difference in mean IVMD change through 24 months.

52. Secondary Outcome

Title	Change in E Wave/A Wave Ratio (E:A Ratio) From Randomization to 6 Months
Description	The endpoint will be a subject's change in E:A ratio (a measure of diastolic function) from randomization to 6 months. The measure for each subject will be the 6 month - randomization visit difference in E:A ratio. Typical values for the E:A ratio at a single time point are 1.04 in men and 1.03 in women.
Time Frame	Randomization to 6 Months

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Biventricular Pacing Arm	Right Ventricular Pacing Arm
Arm/Group Description	Subjects randomized to receive biventricular pacing	Subjects randomized to receive right ventricular pacing.
Measure Participants	221	194
Mean (Standard Deviation) [ratio]	0 (0.6)	0 (0.7)

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Biventricular Pacing Arm, Right Ventricular Pacing Arm
	Comments	The null hypothesis is that patients with AV block, NYHA I-III, and LVEF of at most 50% who receive RV pacing have similar changes in E:A ratio (E/A) through 6 months compared to similar patients who receive BiV pacing. This was tested against the alternative hypothesis that patients have different changes in E:A ratio through 6 months with BiV pacing than RV pacing. Change was calculated as 6 month value - randomization visit value.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value
	Comments
	Method
	Comments
Method of Estimation	Estimation Parameter	Posterior BiV - RV Mean Difference
	Estimated Value	-0.047
	Confidence Interval	(2-Sided) 95%; -0.180 to 0.089
	Parameter Dispersion	Type: Value:
	Estimation Comments	Because Bayesian analyses were employed, a 95% two-sided credible interval was used instead of a confidence interval. This reflects the 2.5th and 97.5th percentile of possible values for the BiV-RV difference in mean E/A change through 6 months.

53. Secondary Outcome

Title	Change in E Wave/A Wave Ratio (E:A Ratio) From Randomization to 12 Months
Description	The endpoint will be a subject's change in E:A ratio (a measure of diastolic function) from randomization to 12 months. The measure for each subject will be the 12 month - randomization visit difference in E:A ratio. Typical values for the E:A ratio at a single time point are 1.04 in men and 1.03 in women.
Time Frame	Randomization to 12 Months

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Biventricular Pacing Arm	Right Ventricular Pacing Arm
Arm/Group Description	Subjects randomized to receive biventricular pacing	Subjects randomized to receive right ventricular pacing.
Measure Participants	208	188
Mean (Standard Deviation) [ratio]	0.1 (0.7)	0.2 (1.0)

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Biventricular Pacing Arm, Right Ventricular Pacing Arm
	Comments	The null hypothesis is that patients with AV block, NYHA I-III, and LVEF of at most 50% who receive RV pacing have similar changes in E:A ratio (E/A) through 12 months compared to similar patients who receive BiV pacing. This was tested against the alternative hypothesis that patients have different changes in E:A ratio through 12 months with BiV pacing than RV pacing. Change was calculated as 12 month value - randomization visit value.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value
	Comments
	Method
	Comments
Method of Estimation	Estimation Parameter	Posterior BiV - RV Mean Difference
	Estimated Value	-0.117
	Confidence Interval	(2-Sided) 95%; -0.287 to 0.058
	Parameter Dispersion	Type: Value:
	Estimation Comments	Because Bayesian analyses were employed, a 95% two-sided credible interval was used instead of a confidence interval. This reflects the 2.5th and 97.5th percentile of possible values for the BiV-RV difference in mean E/A change through 12 months.

54. Secondary Outcome

Title	Change in E Wave/A Wave Ratio (E:A Ratio) From Randomization to 18 Months
Description	The endpoint will be a subject's change in E:A ratio (a measure of diastolic function) from randomization to 18 months. The measure for each subject will be the 18 month - randomization visit difference in E:A ratio. Typical values for the E:A ratio at a single time point are 1.04 in men and 1.03 in women.
Time Frame	Randomization to 18 Months

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Biventricular Pacing Arm	Right Ventricular Pacing Arm
Arm/Group Description	Subjects randomized to receive biventricular pacing	Subjects randomized to receive right ventricular pacing.
Measure Participants	174	159
Mean (Standard Deviation) [ratio]	0.1 (0.8)	0.1 (0.8)

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Biventricular Pacing Arm, Right Ventricular Pacing Arm
	Comments	The null hypothesis is that patients with AV block, NYHA I-III, and LVEF of at most 50% who receive RV pacing have similar changes in E:A ratio (E/A) through 18 months compared to similar patients who receive BiV pacing. This was tested against the alternative hypothesis that patients have different changes in E:A ratio through 18 months with BiV pacing than RV pacing. Change was calculated as 18 month value - randomization visit value.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value
	Comments
	Method
	Comments
Method of Estimation	Estimation Parameter	Posterior BiV - RV Mean Difference
	Estimated Value	0.041
	Confidence Interval	(2-Sided) 95%; -0.136 to 0.220
	Parameter Dispersion	Type: Value:
	Estimation Comments	Because Bayesian analyses were employed, a 95% two-sided credible interval was used instead of a confidence interval. This reflects the 2.5th and 97.5th percentile of possible values for the BiV-RV difference in mean E/A change through 18 months.

55. Secondary Outcome

Title	Change in E Wave/A Wave Ratio (E:A Ratio) From Randomization to 24 Months
Description	The endpoint will be a subject's change in E:A ratio (a measure of diastolic function) from randomization to 24 months. The measure for each subject will be the 24 month - randomization visit difference in E:A ratio. Typical values for the E:A ratio at a single time point are 1.04 in men and 1.03 in women.
Time Frame	Randomization to 24 Months

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Biventricular Pacing Arm	Right Ventricular Pacing Arm
Arm/Group Description	Subjects randomized to receive biventricular pacing	Subjects randomized to receive right ventricular pacing.
Measure Participants	160	141
Mean (Standard Deviation) [ratio]	0.2 (0.8)	0.1 (0.9)

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Biventricular Pacing Arm, Right Ventricular Pacing Arm
	Comments	The null hypothesis is that patients with AV block, NYHA I-III, and LVEF of at most 50% who receive RV pacing have similar changes in E:A ratio (E/A) through 24 months compared to similar patients who receive BiV pacing. This was tested against the alternative hypothesis that patients have different changes in E:A ratio through 24 months with BiV pacing than RV pacing. Change was calculated as 24 month value - randomization visit value.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value
	Comments
	Method
	Comments
Method of Estimation	Estimation Parameter	Posterior BiV - RV Mean Difference
	Estimated Value	0.110
	Confidence Interval	(2-Sided) 95%; -0.085 to 0.311
	Parameter Dispersion	Type: Value:
	Estimation Comments	Because Bayesian analyses were employed, a 95% two-sided credible interval was used instead of a confidence interval. This reflects the 2.5th and 97.5th percentile of possible values for the BiV-RV difference in mean E/A change through 24 months.

56. Secondary Outcome

Title	Clinical Composite Score at 6 Months
Description	The endpoint will be a subject's Clinical Composite Score at 6 months. The Clinical Composite Score is a 3 point score (Worsened, Unchanged, and Improved) based on a number of factors including: whether the subject has died, whether the subject has experienced a heart failure-related hospitalization, whether the subject has discontinued their therapy due to worsening heart failure, whether their New York Heart Association classification has improved or worsened since randomization, and whether they feel moderately or markedly better since randomization.
Time Frame	Randomization to 6 Months

Outcome Measure Data

Analysis Population Description

Only randomized subjects in both device groups were included in the analysis of this endpoint, as the analysis was restricted to post-randomization data. Subjects in the "No Implant Attempt", "Unsuccessful Implants", "CRT-P: Not Randomized", and "CRT-D: Not Randomized" subgroups were excluded.

Arm/Group Title	Biventricular Pacing Arm	Right Ventricular Pacing Arm
Arm/Group Description	Subjects randomized to receive biventricular pacing	Subjects randomized to receive right ventricular pacing.
Measure Participants	349	342
Improved	184 168.8%	133 260.8%
Unchanged	83 76.1%	113 221.6%
Worsened	82 75.2%	96 188.2%

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Biventricular Pacing Arm, Right Ventricular Pacing Arm
	Comments	The null hypothesis is that patients with AV block, NYHA I-III, and LVEF of at most 50% who receive RV pacing have similar Clinical Composite Scores after 6 months compared to similar patients who receive BiV pacing. This was tested against the alternative hypothesis that patients had better scores with BiV pacing than RV pacing. The analysis assigned numerical values (Improved=3, Unchanged=2, Worsened=1) and compared the average score between randomization arms using a one-sided analysis.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value	0.9985
	Comments	BLOCK HF is a Bayesian study; a p-value was not used. Instead, a posterior probability, representing the probability that subjects with biventricular pacing have better outcomes, was calculated. A probability ≥ 0.95 was significant.
	Method	Posterior probability of mean difference
	Comments	The posterior probability that the mean difference is greater than 0 was calculated.
Method of Estimation	Estimation Parameter	Mean Difference (Final Values)
	Estimated Value	0.1841
	Confidence Interval	() 95%; to
	Parameter Dispersion	Type: Value:
	Estimation Comments	This was a one-sided analysis of the BiV arm - RV arm difference in Mean Clinical Composite Scores. Values above 0 suggested better outcomes in the Biventricular arm.

57. Secondary Outcome

Title	Clinical Composite Score at 12 Months
Description	The endpoint will be a subject's Clinical Composite Score at 12 months. The Clinical Composite Score is a 3 point score (Worsened, Unchanged, and Improved) based on a number of factors including: whether the subject has died, whether the subject has experienced a heart failure-related hospitalization, whether the subject has discontinued their therapy due to worsening heart failure, whether their New York Heart Association classification has improved or worsened since randomization, and whether they feel moderately or markedly better since randomization.
Time Frame	Randomization to 12 Months

Outcome Measure Data

Analysis Population Description

Only randomized subjects in both device groups were included in the analysis of this endpoint, as the analysis was restricted to post-randomization data. Subjects in the "No Implant Attempt", "Unsuccessful Implants", "CRT-P: Not Randomized", and "CRT-D: Not Randomized" subgroups were excluded.

Arm/Group Title	Biventricular Pacing Arm	Right Ventricular Pacing Arm
Arm/Group Description	Subjects randomized to receive biventricular pacing who either worsened prior to the 12 month visit or did not miss their 12 month visit due to study closure	Subjects randomized to receive right ventricular pacing who either worsened prior to the 12 month visit or did not miss their 12 month visit due to study closure
Measure Participants	345	341
Improved	160 146.8%	117 229.4%
Unchanged	82 75.2%	78 152.9%
Worsened	103 94.5%	146 286.3%

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Biventricular Pacing Arm, Right Ventricular Pacing Arm
	Comments	The null hypothesis is that patients with AV block, NYHA I-III, and LVEF of at most 50% who receive RV pacing have similar Clinical Composite Scores after 12 months compared to similar patients who receive BiV pacing. This was tested against the alternative hypothesis that patients had better scores with BiV pacing than RV pacing. The analysis assigned numerical values (Improved=3, Unchanged=2, Worsened=1) and compared the average score between randomization arms using a one-sided analysis.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value	0.9999
	Comments	BLOCK HF is a Bayesian study; a p-value was not used. Instead, a posterior probability, representing the probability that subjects with biventricular pacing have better outcomes, was calculated. A probability ≥ 0.95 was significant.
	Method	Posterior probability of mean difference
	Comments	The posterior probability that the mean difference is greater than 0 was calculated.
Method of Estimation	Estimation Parameter	Mean Difference (Final Values)
	Estimated Value	0.2503
	Confidence Interval	() 95%; to
	Parameter Dispersion	Type: Value:
	Estimation Comments	This was a one-sided analysis of the BiV arm - RV arm difference in Mean Clinical Composite Scores. Values above 0 suggested better outcomes in the Biventricular arm.

58. Secondary Outcome

Title	Clinical Composite Score at 18 Months
Description	The endpoint will be a subject's Clinical Composite Score at 18 months. The Clinical Composite Score is a 3 point score (Worsened, Unchanged, and Improved) based on a number of factors including: whether the subject has died, whether the subject has experienced a heart failure-related hospitalization, whether the subject has discontinued their therapy due to worsening heart failure, whether their New York Heart Association classification has improved or worsened since randomization, and whether they feel moderately or markedly better since randomization.
Time Frame	Randomization to 18 Months

Outcome Measure Data

Analysis Population Description

Only randomized subjects in both device groups were included in the analysis of this endpoint, as the analysis was restricted to post-randomization data. Subjects in the "No Implant Attempt", "Unsuccessful Implants", "CRT-P: Not Randomized", and "CRT-D: Not Randomized" subgroups were excluded.

Arm/Group Title	Biventricular Pacing Arm	Right Ventricular Pacing Arm
Arm/Group Description	Subjects randomized to receive biventricular pacing who either worsened prior to the 18 month visit or did not miss their 18 month visit due to study closure	Subjects randomized to receive right ventricular pacing who either worsened prior to the 18 month visit or did not miss their 18 month visit due to study closure
Measure Participants	325	323
Improved	137 125.7%	103 202%
Unchanged	68 62.4%	70 137.3%
Worsened	120 110.1%	150 294.1%

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Biventricular Pacing Arm, Right Ventricular Pacing Arm
	Comments	The null hypothesis is that patients with AV block, NYHA I-III, and LVEF of at most 50% who receive RV pacing have similar Clinical Composite Scores after 18 months compared to similar patients who receive BiV pacing. This was tested against the alternative hypothesis that patients had better scores with BiV pacing than RV pacing. The analysis assigned numerical values (Improved=3, Unchanged=2, Worsened=1) and compared the average score between randomization arms using a one-sided analysis.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value	0.9978
	Comments	BLOCK HF is a Bayesian study; a p-value was not used. Instead, a posterior probability, representing the probability that subjects with biventricular pacing have better outcomes, was calculated. A probability ≥ 0.95 was significant.
	Method	Posterior probability of mean difference
	Comments	The posterior probability that the mean difference is greater than 0 was calculated.
Method of Estimation	Estimation Parameter	Mean Difference (Final Values)
	Estimated Value	0.1978
	Confidence Interval	() 95%; to
	Parameter Dispersion	Type: Value:
	Estimation Comments	This was a one-sided analysis of the BiV arm - RV arm difference in Mean Clinical Composite Scores. Values above 0 suggested better outcomes in the Biventricular arm.

59. Secondary Outcome

Title	Clinical Composite Score at 24 Months
Description	The endpoint will be a subject's Clinical Composite Score at 24 months. The Clinical Composite Score is a 3 point score (Worsened, Unchanged, and Improved) based on a number of factors including: whether the subject has died, whether the subject has experienced a heart failure-related hospitalization, whether the subject has discontinued their therapy due to worsening heart failure, whether their New York Heart Association classification has improved or worsened since randomization, and whether they feel moderately or markedly better since randomization.
Time Frame	Randomization to 24 Months

Outcome Measure Data

Analysis Population Description

Only randomized subjects in both device groups were included in the analysis of this endpoint, as the analysis was restricted to post-randomization data. Subjects in the "No Implant Attempt", "Unsuccessful Implants", "CRT-P: Not Randomized", and "CRT-D: Not Randomized" subgroups were excluded.

Arm/Group Title	Biventricular Pacing Arm	Right Ventricular Pacing Arm
Arm/Group Description	Subjects randomized to receive biventricular pacing who either worsened prior to the 24 month visit or did not miss their 24 month visit due to study closure	Subjects randomized to receive right ventricular pacing who either worsened prior to the 24 month visit or did not miss their 24 month visit due to study closure
Measure Participants	308	314
Improved	118 108.3%	94 184.3%
Unchanged	70 64.2%	59 115.7%
Worsened	120 110.1%	161 315.7%

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Biventricular Pacing Arm, Right Ventricular Pacing Arm
	Comments	The null hypothesis is that patients with AV block, NYHA I-III, and LVEF of at most 50% who receive RV pacing have similar Clinical Composite Scores after 24 months compared to similar patients who receive BiV pacing. This was tested against the alternative hypothesis that patients had better scores with BiV pacing than RV pacing. The analysis assigned numerical values (Improved=3, Unchanged=2, Worsened=1) and compared the average score between randomization arms using a one-sided analysis.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value	0.9983
	Comments	BLOCK HF is a Bayesian study; a p-value was not used. Instead, a posterior probability, representing the probability that subjects with biventricular pacing have better outcomes, was calculated. A probability ≥ 0.95 was significant.
	Method	Posterior probability of mean difference
	Comments	The posterior probability that the mean difference is greater than 0 was calculated.
Method of Estimation	Estimation Parameter	Mean Difference (Final Values)
	Estimated Value	0.2069
	Confidence Interval	() 95%; to
	Parameter Dispersion	Type: Value:
	Estimation Comments	This was a one-sided analysis of the BiV arm - RV arm difference in Mean Clinical Composite Scores. Values above 0 suggested better outcomes in the Biventricular arm.

60. Secondary Outcome

Title	CRT-P and CRT-D System Implant Success
Description	The endpoint will be whether each subject who underwent an implant attempt of a Cardiac Resynchronization Therapy device, be it a pacing only device (CRT-P) or a pacing device with defibrillation capability (CRT-D), had a successful procedure (i.e. the generator, left ventricular lead, and right ventricular lead were successfully implanted). Only one implant attempt was allowed.
Time Frame	Initial Implant Procedure

Outcome Measure Data

Analysis Population Description

For this outcome measure, only subjects in the "No Implant Attempt" subgroup were excluded.

Arm/Group Title	Subjects With a CRT-P Implant Attempt	Subjects With a CRT-D Implant Attempt
Arm/Group Description	Subjects who underwent an implant attempt for a CRT-P device	Subjects who underwent an implant attempt for a CRT-D device
Measure Participants	561	248
Subjects successfully implanted	531 487.2%	227 445.1%
Subjects not successfully implanted	30 27.5%	21 41.2%

61. Secondary Outcome

Title	Incidence of Ventricular Tachyarrhythmias
Description	Among subjects implanted with a Cardiac Resynchronization Therapy with Defibrillation device (CRT-D) and randomized, the endpoint was the time from randomization until the subject experienced a ventricular tachyarrhythmia. For each randomization arm, the number of CRT-D subjects who experienced at least one ventricular tachyarrhythmia post-randomization is reported, as well as the number of CRT-D subjects who did not experience one or more ventricular tachyarrhythmias post-randomization.
Time Frame	Participants were followed for the duration of the study, an average of 37.9 months post-randomization among CRT-D subjects.

Outcome Measure Data

Analysis Population Description

Only randomized subjects in the CRT-D device group were included in the analysis of this endpoint, as the analysis was restricted to post-randomization data recorded by CRT-D devices. Subjects in the "No Implant Attempt", "Unsuccessful Implants", "CRT-D: Not Randomized", and all CRT-P subgroups were excluded.

Arm/Group Title	CRT-D: Biventricular Pacing Arm	CRT-D: Right Ventricular Pacing Arm
Arm/Group Description	Subjects implanted with a CRT-D device and randomized to receive biventricular pacing	Subjects implanted with a CRT-D device and randomized to receive right ventricular pacing
Measure Participants	106	101
Subjects who experienced VT/VF	39 35.8%	31 60.8%
Subjects who did not experience VT/VF	67 61.5%	70 137.3%

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Biventricular Pacing Arm, Right Ventricular Pacing Arm
	Comments	The null hypothesis is that patients with AV block, ejection fractions of at most 50%, NYHA classifications of I-III, and indicated for defibrillation therapy who receive biventricular (BiV) pacing have the same rate of experiencing their first ventricular arrhythmia as corresponding patients who receive right ventricular pacing. This was tested against the one-side hypothesis that patients with BiV pacing have a lower risk of ventricular arrhythmias than subjects with right ventricular pacing.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value	0.189
	Comments	BLOCK HF is a Bayesian study; a p-value was not used. Instead, a posterior probability, representing the probability that subjects with biventricular pacing have better outcomes, were calculated. A probability ≥ 0.95 was significant.
	Method	Posterior Distribution for HR
	Comments	The posterior distribution is the set of values the BiV to RV hazard ratio can take, and its likelihood of taking such values.
Method of Estimation	Estimation Parameter	Hazard Ratio (HR)
	Estimated Value	1.23
	Confidence Interval	(2-Sided) 95%; 0.78 to 2.01
	Parameter Dispersion	Type: Value:
	Estimation Comments	The hazard ratio corresponds to the time from randomization to first ventricular arrhythmia occurring post-randomization for each subject. Ventricular arrhythmias occurring prior to randomization were excluded. A 95% credible interval was used.

Adverse Events

Time Frame	Reported Adverse Events (AEs) include events starting on or after the date of consent and on or before the date of exit
Adverse Event Reporting Description	If a subject experienced more than 1 of a given AE, the subject is counted only once for that AE. In the case of the BiV and RV randomized arms, both pre-randomization and post-randomization adverse events are included.
Arm/Group Title	Biventricular Pacing Arm		Right Ventricular Pacing Arm		CRT: Not Randomized		Unsuccessful Implants		No Implant Attempt
Arm/Group Description	Subjects who were implanted with a CRT device and randomized to receive biventricular pacing		Subjects who were implanted with a CRT device and randomized to receive right ventricular pacing		Subjects successfully implanted with a CRT device who were not randomized		Subjects who underwent an implant attempt of a CRT-P or CRT-D device but were not successfully implanted		Subjects who did not undergo an implant attempt of a CRT-P or CRT-D device and were not randomized
All Cause Mortality
	Biventricular Pacing Arm		Right Ventricular Pacing Arm		CRT: Not Randomized		Unsuccessful Implants		No Implant Attempt
	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events
Total	/ (NaN)		/ (NaN)		/ (NaN)		/ (NaN)		/ (NaN)
Serious Adverse Events
	Biventricular Pacing Arm		Right Ventricular Pacing Arm		CRT: Not Randomized		Unsuccessful Implants		No Implant Attempt
	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events
Total	223/349 (63.9%)		219/342 (64%)		41/67 (61.2%)		6/51 (11.8%)		2/109 (1.8%)
Blood and lymphatic system disorders
Anaemia	3/349 (0.9%)	3	3/342 (0.9%)	5	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Anaemia of chronic disease	1/349 (0.3%)	4	0/342 (0%)	0	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Coagulopathy	0/349 (0%)	0	1/342 (0.3%)	1	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Lymphadenitis	0/349 (0%)	0	1/342 (0.3%)	1	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Cardiac disorders
Acute coronary syndrome	8/349 (2.3%)	11	8/342 (2.3%)	8	1/67 (1.5%)	1	0/51 (0%)	0	0/109 (0%)	0
Acute myocardial infarction	7/349 (2%)	7	3/342 (0.9%)	3	2/67 (3%)	2	0/51 (0%)	0	0/109 (0%)	0
Angina pectoris	9/349 (2.6%)	10	10/342 (2.9%)	11	1/67 (1.5%)	1	0/51 (0%)	0	0/109 (0%)	0
Angina unstable	5/349 (1.4%)	7	6/342 (1.8%)	7	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Aortic valve incompetence	0/349 (0%)	0	0/342 (0%)	0	1/67 (1.5%)	1	0/51 (0%)	0	0/109 (0%)	0
Atrial fibrillation	14/349 (4%)	19	26/342 (7.6%)	37	1/67 (1.5%)	1	0/51 (0%)	0	0/109 (0%)	0
Atrial flutter	4/349 (1.1%)	6	4/342 (1.2%)	6	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Atrial tachycardia	0/349 (0%)	0	2/342 (0.6%)	2	1/67 (1.5%)	1	0/51 (0%)	0	0/109 (0%)	0
Cardiac arrest	5/349 (1.4%)	5	6/342 (1.8%)	6	1/67 (1.5%)	1	0/51 (0%)	0	0/109 (0%)	0
Cardiac failure	100/349 (28.7%)	196	117/342 (34.2%)	215	20/67 (29.9%)	28	2/51 (3.9%)	2	0/109 (0%)	0
Cardiac tamponade	4/349 (1.1%)	4	0/342 (0%)	0	1/67 (1.5%)	1	0/51 (0%)	0	0/109 (0%)	0
Cardiac valve disease	0/349 (0%)	0	1/342 (0.3%)	1	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Cardio-respiratory arrest	2/349 (0.6%)	2	3/342 (0.9%)	3	1/67 (1.5%)	1	0/51 (0%)	0	0/109 (0%)	0
Cardiomyopathy	1/349 (0.3%)	1	3/342 (0.9%)	3	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Coronary artery disease	10/349 (2.9%)	10	6/342 (1.8%)	7	1/67 (1.5%)	2	0/51 (0%)	0	1/109 (0.9%)	1
Intracardiac thrombus	1/349 (0.3%)	1	0/342 (0%)	0	1/67 (1.5%)	1	0/51 (0%)	0	1/109 (0.9%)	1
Mitral valve incompetence	1/349 (0.3%)	1	1/342 (0.3%)	1	1/67 (1.5%)	1	0/51 (0%)	0	0/109 (0%)	0
Myocardial infarction	1/349 (0.3%)	1	6/342 (1.8%)	6	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Pericardial effusion	1/349 (0.3%)	1	1/342 (0.3%)	1	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Stress cardiomyopathy	1/349 (0.3%)	1	0/342 (0%)	0	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Supraventricular tachycardia	0/349 (0%)	0	1/342 (0.3%)	1	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Tachycardia	0/349 (0%)	0	1/342 (0.3%)	1	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Ventricular arrhythmia	1/349 (0.3%)	1	1/342 (0.3%)	1	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Ventricular fibrillation	5/349 (1.4%)	6	7/342 (2%)	7	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Ventricular tachycardia	11/349 (3.2%)	17	14/342 (4.1%)	20	1/67 (1.5%)	3	0/51 (0%)	0	0/109 (0%)	0
Eye disorders
Amaurosis fugax	1/349 (0.3%)	1	1/342 (0.3%)	2	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Gastrointestinal disorders
Gastritis atrophic	1/349 (0.3%)	1	0/342 (0%)	0	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Gastrointestinal haemorrhage	0/349 (0%)	0	1/342 (0.3%)	1	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Pancreatitis	1/349 (0.3%)	1	0/342 (0%)	0	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Retroperitoneal haemorrhage	0/349 (0%)	0	1/342 (0.3%)	1	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
General disorders
Adverse drug reaction	5/349 (1.4%)	5	7/342 (2%)	8	0/67 (0%)	0	1/51 (2%)	1	0/109 (0%)	0
Asthenia	1/349 (0.3%)	1	0/342 (0%)	0	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Chest discomfort	1/349 (0.3%)	1	0/342 (0%)	0	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Chest pain	3/349 (0.9%)	3	3/342 (0.9%)	5	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Implant site erosion	1/349 (0.3%)	1	0/342 (0%)	0	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Implant site haematoma	1/349 (0.3%)	1	2/342 (0.6%)	2	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Implant site pain	1/349 (0.3%)	1	0/342 (0%)	0	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Multi-organ failure	1/349 (0.3%)	1	0/342 (0%)	0	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Non-cardiac chest pain	2/349 (0.6%)	2	0/342 (0%)	0	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Oedema peripheral	0/349 (0%)	0	1/342 (0.3%)	1	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Sudden death	1/349 (0.3%)	1	2/342 (0.6%)	2	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Immune system disorders
Sarcoidosis	1/349 (0.3%)	1	0/342 (0%)	0	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Infections and infestations
Bacteraemia	2/349 (0.6%)	2	0/342 (0%)	0	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Bacterial pyelonephritis	0/349 (0%)	0	1/342 (0.3%)	1	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Bronchitis	4/349 (1.1%)	4	4/342 (1.2%)	4	1/67 (1.5%)	1	0/51 (0%)	0	0/109 (0%)	0
Cellulitis	1/349 (0.3%)	1	4/342 (1.2%)	4	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Device related infection	0/349 (0%)	0	1/342 (0.3%)	1	2/67 (3%)	2	0/51 (0%)	0	0/109 (0%)	0
Diabetic foot infection	0/349 (0%)	0	1/342 (0.3%)	1	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Endocarditis	1/349 (0.3%)	1	2/342 (0.6%)	2	1/67 (1.5%)	1	0/51 (0%)	0	0/109 (0%)	0
Escherichia bacteraemia	1/349 (0.3%)	1	0/342 (0%)	0	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Gangrene	0/349 (0%)	0	1/342 (0.3%)	1	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Implant site cellulitis	1/349 (0.3%)	1	0/342 (0%)	0	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Implant site infection	2/349 (0.6%)	2	2/342 (0.6%)	2	1/67 (1.5%)	1	0/51 (0%)	0	0/109 (0%)	0
Klebsiella infection	1/349 (0.3%)	1	0/342 (0%)	0	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Lower respiratory tract infection	1/349 (0.3%)	1	0/342 (0%)	0	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Lung infection	1/349 (0.3%)	1	0/342 (0%)	0	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Osteomyelitis	1/349 (0.3%)	1	1/342 (0.3%)	2	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Osteomyelitis chronic	1/349 (0.3%)	1	0/342 (0%)	0	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Pneumonia	28/349 (8%)	57	37/342 (10.8%)	50	6/67 (9%)	8	0/51 (0%)	0	0/109 (0%)	0
Pyelonephritis	0/349 (0%)	0	1/342 (0.3%)	1	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Sepsis	0/349 (0%)	0	1/342 (0.3%)	1	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Sepsis syndrome	1/349 (0.3%)	1	1/342 (0.3%)	1	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Septic shock	0/349 (0%)	0	1/342 (0.3%)	1	1/67 (1.5%)	1	0/51 (0%)	0	0/109 (0%)	0
Staphylococcal sepsis	0/349 (0%)	0	1/342 (0.3%)	1	1/67 (1.5%)	1	0/51 (0%)	0	0/109 (0%)	0
Urinary tract infection	7/349 (2%)	9	6/342 (1.8%)	6	2/67 (3%)	2	0/51 (0%)	0	0/109 (0%)	0
Urosepsis	4/349 (1.1%)	4	2/342 (0.6%)	2	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Vaginitis bacterial	0/349 (0%)	0	1/342 (0.3%)	1	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Injury, poisoning and procedural complications
Arterial injury	0/349 (0%)	0	0/342 (0%)	0	1/67 (1.5%)	1	0/51 (0%)	0	0/109 (0%)	0
Arteriovenous fistula site complication	1/349 (0.3%)	1	0/342 (0%)	0	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Arteriovenous fistula site haemorrhage	1/349 (0.3%)	1	0/342 (0%)	0	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Arteriovenous fistula thrombosis	1/349 (0.3%)	1	0/342 (0%)	0	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Arteriovenous graft thrombosis	1/349 (0.3%)	1	0/342 (0%)	0	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Cardiac procedure complication	0/349 (0%)	0	1/342 (0.3%)	1	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Cervical vertebral fracture	1/349 (0.3%)	1	0/342 (0%)	0	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Complication of device insertion	0/349 (0%)	0	1/342 (0.3%)	1	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Defibrillation threshold increased	0/349 (0%)	0	1/342 (0.3%)	1	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Device failure	0/349 (0%)	0	1/342 (0.3%)	1	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Device lead damage	3/349 (0.9%)	3	3/342 (0.9%)	3	1/67 (1.5%)	1	0/51 (0%)	0	0/109 (0%)	0
Device migration	0/349 (0%)	0	1/342 (0.3%)	1	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Dialysis device complication	1/349 (0.3%)	1	0/342 (0%)	0	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Elevated pacing threshold	1/349 (0.3%)	1	1/342 (0.3%)	1	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Failure to capture	2/349 (0.6%)	2	4/342 (1.2%)	4	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Inappropriate device stimulation of tissue	6/349 (1.7%)	6	1/342 (0.3%)	1	1/67 (1.5%)	1	0/51 (0%)	0	0/109 (0%)	0
Lead dislodgement	12/349 (3.4%)	13	13/342 (3.8%)	15	3/67 (4.5%)	3	3/51 (5.9%)	3	0/109 (0%)	0
Lower limb fracture	1/349 (0.3%)	1	0/342 (0%)	0	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Oversensing	1/349 (0.3%)	1	0/342 (0%)	0	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Pacemaker complication	1/349 (0.3%)	1	0/342 (0%)	0	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Pneumothorax traumatic	0/349 (0%)	0	1/342 (0.3%)	1	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Post procedural haemorrhage	0/349 (0%)	0	2/342 (0.6%)	2	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Procedural hypotension	2/349 (0.6%)	2	2/342 (0.6%)	2	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Subdural haematoma	1/349 (0.3%)	1	3/342 (0.9%)	3	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Investigations
Ejection fraction decreased	1/349 (0.3%)	1	3/342 (0.9%)	3	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Metabolism and nutrition disorders
Dehydration	14/349 (4%)	16	13/342 (3.8%)	14	1/67 (1.5%)	1	0/51 (0%)	0	0/109 (0%)	0
Diabetic foot	1/349 (0.3%)	2	0/342 (0%)	0	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Failure to thrive	1/349 (0.3%)	1	0/342 (0%)	0	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Hyperkalaemia	2/349 (0.6%)	2	2/342 (0.6%)	2	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Hypokalaemia	0/349 (0%)	0	1/342 (0.3%)	1	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Hyponatraemia	0/349 (0%)	0	1/342 (0.3%)	1	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Neoplasms benign, malignant and unspecified (incl cysts and polyps)
Bladder cancer	1/349 (0.3%)	2	2/342 (0.6%)	2	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Bronchial carcinoma	0/349 (0%)	0	1/342 (0.3%)	1	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Laryngeal cancer	1/349 (0.3%)	1	0/342 (0%)	0	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Lung adenocarcinoma	0/349 (0%)	0	1/342 (0.3%)	1	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Lung cancer metastatic	0/349 (0%)	0	1/342 (0.3%)	1	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Lung neoplasm malignant	0/349 (0%)	0	2/342 (0.6%)	2	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Non-small cell lung cancer	0/349 (0%)	0	0/342 (0%)	0	1/67 (1.5%)	1	0/51 (0%)	0	0/109 (0%)	0
Prostate cancer	1/349 (0.3%)	1	0/342 (0%)	0	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Prostate cancer metastatic	1/349 (0.3%)	1	0/342 (0%)	0	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Renal cell carcinoma stage unspecified	0/349 (0%)	0	1/342 (0.3%)	2	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Small cell lung cancer stage unspecified	1/349 (0.3%)	1	0/342 (0%)	0	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Ureteric cancer	0/349 (0%)	0	1/342 (0.3%)	1	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Nervous system disorders
Aphasia	1/349 (0.3%)	1	1/342 (0.3%)	1	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Carotid artery disease	1/349 (0.3%)	1	0/342 (0%)	0	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Carotid artery stenosis	2/349 (0.6%)	2	4/342 (1.2%)	4	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Cerebral artery embolism	1/349 (0.3%)	1	0/342 (0%)	0	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Cerebral haemorrhage	3/349 (0.9%)	3	0/342 (0%)	0	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Cerebrovascular accident	10/349 (2.9%)	12	14/342 (4.1%)	16	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Convulsion	0/349 (0%)	0	1/342 (0.3%)	1	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Encephalopathy	1/349 (0.3%)	1	0/342 (0%)	0	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Haemorrhage intracranial	1/349 (0.3%)	1	0/342 (0%)	0	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Intraventricular haemorrhage	0/349 (0%)	0	3/342 (0.9%)	3	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Ischaemic stroke	0/349 (0%)	0	1/342 (0.3%)	1	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Presyncope	0/349 (0%)	0	1/342 (0.3%)	1	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Syncope	3/349 (0.9%)	3	8/342 (2.3%)	9	1/67 (1.5%)	1	0/51 (0%)	0	0/109 (0%)	0
Transient ischaemic attack	4/349 (1.1%)	4	7/342 (2%)	7	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Psychiatric disorders
Confusional state	1/349 (0.3%)	1	0/342 (0%)	0	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Renal and urinary disorders
Bladder obstruction	1/349 (0.3%)	1	0/342 (0%)	0	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Calculus bladder	0/349 (0%)	0	1/342 (0.3%)	1	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Calculus ureteric	0/349 (0%)	0	1/342 (0.3%)	1	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Calculus urinary	1/349 (0.3%)	1	0/342 (0%)	0	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Cystitis glandularis	0/349 (0%)	0	0/342 (0%)	0	1/67 (1.5%)	1	0/51 (0%)	0	0/109 (0%)	0
Haematuria	4/349 (1.1%)	4	1/342 (0.3%)	1	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Nephrolithiasis	1/349 (0.3%)	1	0/342 (0%)	0	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Obstructive uropathy	1/349 (0.3%)	1	0/342 (0%)	0	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Renal artery stenosis	1/349 (0.3%)	1	0/342 (0%)	0	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Renal cyst	0/349 (0%)	0	1/342 (0.3%)	1	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Renal failure	4/349 (1.1%)	4	6/342 (1.8%)	6	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Renal failure acute	18/349 (5.2%)	20	15/342 (4.4%)	17	3/67 (4.5%)	4	0/51 (0%)	0	0/109 (0%)	0
Renal failure chronic	5/349 (1.4%)	5	1/342 (0.3%)	1	1/67 (1.5%)	1	0/51 (0%)	0	0/109 (0%)	0
Renal infarct	1/349 (0.3%)	1	0/342 (0%)	0	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Urinary retention	1/349 (0.3%)	1	1/342 (0.3%)	1	1/67 (1.5%)	1	0/51 (0%)	0	0/109 (0%)	0
Respiratory, thoracic and mediastinal disorders
Acute respiratory failure	0/349 (0%)	0	1/342 (0.3%)	1	1/67 (1.5%)	1	0/51 (0%)	0	0/109 (0%)	0
Asthma	0/349 (0%)	0	1/342 (0.3%)	1	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Chronic obstructive pulmonary disease	17/349 (4.9%)	23	11/342 (3.2%)	17	1/67 (1.5%)	1	0/51 (0%)	0	0/109 (0%)	0
Dyspnoea	1/349 (0.3%)	1	5/342 (1.5%)	6	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Dyspnoea exertional	0/349 (0%)	0	1/342 (0.3%)	1	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Epistaxis	2/349 (0.6%)	5	0/342 (0%)	0	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Haemopneumothorax	1/349 (0.3%)	1	1/342 (0.3%)	1	0/67 (0%)	0	1/51 (2%)	1	0/109 (0%)	0
Haemoptysis	0/349 (0%)	0	2/342 (0.6%)	2	1/67 (1.5%)	1	0/51 (0%)	0	0/109 (0%)	0
Hypoxia	0/349 (0%)	0	2/342 (0.6%)	2	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Interstitial lung disease	1/349 (0.3%)	1	0/342 (0%)	0	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Mediastinal mass	1/349 (0.3%)	1	0/342 (0%)	0	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Pneumonia aspiration	5/349 (1.4%)	5	2/342 (0.6%)	2	1/67 (1.5%)	1	0/51 (0%)	0	0/109 (0%)	0
Pneumothorax	1/349 (0.3%)	1	0/342 (0%)	0	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Pulmonary embolism	3/349 (0.9%)	3	2/342 (0.6%)	3	1/67 (1.5%)	1	0/51 (0%)	0	0/109 (0%)	0
Pulmonary mass	1/349 (0.3%)	1	0/342 (0%)	0	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Pulmonary oedema	0/349 (0%)	0	0/342 (0%)	0	1/67 (1.5%)	1	0/51 (0%)	0	0/109 (0%)	0
Respiratory arrest	1/349 (0.3%)	1	0/342 (0%)	0	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Respiratory failure	5/349 (1.4%)	5	6/342 (1.8%)	6	2/67 (3%)	2	0/51 (0%)	0	0/109 (0%)	0
Skin and subcutaneous tissue disorders
Drug eruption	1/349 (0.3%)	1	0/342 (0%)	0	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Skin ulcer	2/349 (0.6%)	2	4/342 (1.2%)	5	1/67 (1.5%)	1	0/51 (0%)	0	0/109 (0%)	0
Surgical and medical procedures
Cardiac pacemaker insertion	0/349 (0%)	0	1/342 (0.3%)	1	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Medical device change	39/349 (11.2%)	39	23/342 (6.7%)	24	3/67 (4.5%)	3	0/51 (0%)	0	0/109 (0%)	0
Medical device implantation	0/349 (0%)	0	0/342 (0%)	0	1/67 (1.5%)	1	0/51 (0%)	0	0/109 (0%)	0
Vascular disorders
Aortic aneurysm	2/349 (0.6%)	2	3/342 (0.9%)	3	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Aortic arteriosclerosis	1/349 (0.3%)	1	0/342 (0%)	0	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Aortic stenosis	0/349 (0%)	0	1/342 (0.3%)	1	2/67 (3%)	2	0/51 (0%)	0	0/109 (0%)	0
Arterial occlusive disease	0/349 (0%)	0	1/342 (0.3%)	1	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Deep vein thrombosis	3/349 (0.9%)	3	4/342 (1.2%)	4	1/67 (1.5%)	1	0/51 (0%)	0	0/109 (0%)	0
Femoral artery occlusion	1/349 (0.3%)	1	0/342 (0%)	0	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Haematoma	0/349 (0%)	0	1/342 (0.3%)	1	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Haemorrhage	0/349 (0%)	0	0/342 (0%)	0	1/67 (1.5%)	1	1/51 (2%)	1	0/109 (0%)	0
Hypertensive crisis	2/349 (0.6%)	2	1/342 (0.3%)	1	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Hypotension	2/349 (0.6%)	2	4/342 (1.2%)	5	1/67 (1.5%)	1	0/51 (0%)	0	0/109 (0%)	0
Hypovolaemic shock	0/349 (0%)	0	1/342 (0.3%)	1	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Intermittent claudication	2/349 (0.6%)	2	1/342 (0.3%)	1	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Ischaemic limb pain	0/349 (0%)	0	1/342 (0.3%)	1	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Jugular vein thrombosis	0/349 (0%)	0	1/342 (0.3%)	1	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Orthostatic hypotension	2/349 (0.6%)	2	0/342 (0%)	0	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Peripheral arterial occlusive disease	2/349 (0.6%)	3	1/342 (0.3%)	1	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Peripheral embolism	1/349 (0.3%)	1	0/342 (0%)	0	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Peripheral ischaemia	2/349 (0.6%)	2	0/342 (0%)	0	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Peripheral vascular disorder	8/349 (2.3%)	8	4/342 (1.2%)	5	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Steal syndrome	0/349 (0%)	0	1/342 (0.3%)	1	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Subclavian vein thrombosis	1/349 (0.3%)	1	1/342 (0.3%)	1	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Thrombophlebitis	1/349 (0.3%)	1	1/342 (0.3%)	1	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Vascular insufficiency	1/349 (0.3%)	1	0/342 (0%)	0	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Vasculitis	0/349 (0%)	0	1/342 (0.3%)	1	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Venous occlusion	1/349 (0.3%)	1	0/342 (0%)	0	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Venous thrombosis	0/349 (0%)	0	1/342 (0.3%)	1	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Other (Not Including Serious) Adverse Events
	Biventricular Pacing Arm		Right Ventricular Pacing Arm		CRT: Not Randomized		Unsuccessful Implants		No Implant Attempt
	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events
Total	193/349 (55.3%)		181/342 (52.9%)		16/67 (23.9%)		8/51 (15.7%)		0/109 (0%)
Cardiac disorders
Atrial fibrillation	38/349 (10.9%)	42	33/342 (9.6%)	36	1/67 (1.5%)	1	0/51 (0%)	0	0/109 (0%)	0
Cardiac failure	63/349 (18.1%)	90	77/342 (22.5%)	114	2/67 (3%)	2	0/51 (0%)	0	0/109 (0%)	0
General disorders
Adverse drug reaction	25/349 (7.2%)	30	20/342 (5.8%)	23	0/67 (0%)	0	1/51 (2%)	1	0/109 (0%)	0
Chest pain	19/349 (5.4%)	22	24/342 (7%)	27	0/67 (0%)	0	0/51 (0%)	0	0/109 (0%)	0
Fatigue	12/349 (3.4%)	13	17/342 (5%)	17	1/67 (1.5%)	1	0/51 (0%)	0	0/109 (0%)	0
Infections and infestations
Bronchitis	17/349 (4.9%)	20	23/342 (6.7%)	27	0/67 (0%)	0	1/51 (2%)	1	0/109 (0%)	0
Urinary tract infection	29/349 (8.3%)	41	23/342 (6.7%)	32	5/67 (7.5%)	6	0/51 (0%)	0	0/109 (0%)	0
Injury, poisoning and procedural complications
Cardiac procedure complication	4/349 (1.1%)	4	1/342 (0.3%)	1	1/67 (1.5%)	1	4/51 (7.8%)	4	0/109 (0%)	0
Inappropriate device stimulation of tissue	53/349 (15.2%)	70	14/342 (4.1%)	14	5/67 (7.5%)	6	1/51 (2%)	1	0/109 (0%)	0
Metabolism and nutrition disorders
Dehydration	12/349 (3.4%)	14	19/342 (5.6%)	22	3/67 (4.5%)	3	0/51 (0%)	0	0/109 (0%)	0
Nervous system disorders
Dizziness	12/349 (3.4%)	12	26/342 (7.6%)	27	1/67 (1.5%)	1	0/51 (0%)	0	0/109 (0%)	0
Respiratory, thoracic and mediastinal disorders
Dyspnoea	19/349 (5.4%)	19	29/342 (8.5%)	30	0/67 (0%)	0	1/51 (2%)	1	0/109 (0%)	0

Limitations/Caveats

[Not Specified]

More Information

Certain Agreements

Principal Investigators are NOT employed by the organization sponsoring the study.

There is NOT an agreement between Principal Investigators and the Sponsor (or its agents) that restricts the PI's rights to discuss or publish trial results after the trial is completed.