Pacing Affects Cardiovascular Endpoints in Patients With Right Bundle-Branch Block (The PACE-RBBB Trial)

• Sponsor: Duke University (Other)
• Overall Status: Terminated
• CT.gov ID: NCT01169493
• Collaborator: American Heart Association (Other)
• Enrollment: 16
• Locations: 2
• Arms: 6
• Duration (Months): 43
• Patients Per Site: 8
• Patients Per Site Per Month: 0.2

Study Details

Study Description

Brief Summary

Heart failure (HF) affects 5 million Americans and is responsible for more health-care expenditure than any other medical diagnosis. Approximately half of all HF patients have electrocardiographic prolongation of the QRS interval and ventricular dyssynchrony, a perturbation of the normal pattern of ventricular contraction that reduces the efficiency of ventricular work. Ventricular dyssynchrony is directly responsible for worsening HF symptomatology in this subset of patients. Resynchronization of ventricular contraction is usually achieved through simultaneous pacing of the left and right ventricles using a biventricular (BiV) pacemaker or implantable cardioverter-defibrillator. Clinical trial evidence supporting the use of BiV pacing in patients with prolonged QRS duration was obtained almost exclusively in patients with a left bundle-branch block (LBBB) electrocardiographic pattern. Recent evidence suggests that resynchronization of ventricular contraction in patients with LBBB can be obtained by univentricular left ventricular pacing with equal or superior clinical benefits compared to BiV pacing. Animal studies suggest that ventricular resynchronization can be obtained in subjects with right bundle-branch block (RBBB) through univentricular right ventricular pacing. No clinical trial evidence exists to support the use of BiV pacing in patients with RBBB. Thousands of patients with symptomatic HF and RBBB currently have univentricular ICDs in place for the prevention of sudden cardiac death. Most of these devices are currently programmed to avoid RV pacing. We aim to determine if ventricular resynchronization delivered through univentricular RV pacing improves symptoms in patients with RBBB and moderate to severe HF who have previously undergone BiV ICD implantation for symptomatic heart failure. We further aim to determine if ventricular resynchronization improves myocardial performance and ventricular geometry as detected by echocardiographic measures and quality of life for patients with HF and RBBB. We hypothesize that RV univentricular pacing delivered with an atrio-ventricular interval that maximizes ventricular synchrony is equivalent to BiV pacing for improvement in cardiac performance, HF symptoms, and positive ventricular remodeling in patients with HF and RBBB.

Condition or Disease	Intervention/Treatment	Phase
Heart Failure; Right Bundle-Branch Block	Device: VVI-40; Device: RV DDD-40; Device: BiV DDD-40	N/A

Study Design

• Study Type: Interventional
• Actual Enrollment: 16 participants
• Allocation: Randomized
• Intervention Model: Crossover Assignment
• Masking: Triple (Participant, Investigator, Outcomes Assessor)
• Primary Purpose: Treatment
• Official Title: Pacing Affects Cardiovascular Endpoints in Patients With Right Bundle-Branch Block (The PACE-RBBB Trial)
• Study Start Date: Jan 1, 2011
• Actual Primary Completion Date: Aug 1, 2014
• Actual Study Completion Date: Aug 1, 2014

Arms and Interventions

Arm	Intervention/Treatment
Experimental: VVI-40 to RV DDD-40 to Bi-V DDD-40 Period 1: Participants assigned to VVI-40 Participants will then Crossover to Period 2. Period 2: Participants assigned to RV DDD-40 Participants will then Crossover to Period 3. Period 3: Participants assigned to Bi-V DDD-40	Device: VVI-40; Pacing mode set to VVI-40, RV only pacing; Device: RV DDD-40; ICD programmed to DDD-40, RV only pacing with aan AV interval producing QRS fusion on surface EKG.; Device: BiV DDD-40; ICD programmed to BiV pacing at a lower rate of 40
Experimental: VVI-40 to Bi-V DDD-40 to RV DDD-40 Period 1: Participants assigned to VVI-40 Participants will then Crossover to Period 2. Period 2: Participants assigned to Bi-V DDD-40 Participants will then Crossover to Period 3. Period 3: Participants assigned to RV DDD-40	Device: VVI-40; Pacing mode set to VVI-40, RV only pacing; Device: RV DDD-40; ICD programmed to DDD-40, RV only pacing with aan AV interval producing QRS fusion on surface EKG.; Device: BiV DDD-40; ICD programmed to BiV pacing at a lower rate of 40
Experimental: Bi-V DDD-40 to VVI-40 to RV DDD-40 Period 1: Participants assigned to Bi-V DDD-40 Participants will then Crossover to Period 2. Period 2: Participants assigned to VVI-40 Participants will then Crossover to Period 3. Period 3: Participants assigned to RV DDD-40	Device: VVI-40; Pacing mode set to VVI-40, RV only pacing; Device: RV DDD-40; ICD programmed to DDD-40, RV only pacing with aan AV interval producing QRS fusion on surface EKG.; Device: BiV DDD-40; ICD programmed to BiV pacing at a lower rate of 40
Experimental: Bi-V DDD-40 to RV DDD-40 to VVI-40 Period 1: Participants assigned to Bi-V DDD-40 Participants will then Crossover to Period 2. Period 2: Participants assigned to RV DDD-40 Participants will then Crossover to Period 3. Period 3: Participants assigned to VVI-40	Device: VVI-40; Pacing mode set to VVI-40, RV only pacing; Device: RV DDD-40; ICD programmed to DDD-40, RV only pacing with aan AV interval producing QRS fusion on surface EKG.; Device: BiV DDD-40; ICD programmed to BiV pacing at a lower rate of 40
Experimental: RV DDD-40 to VVI-40 to Bi-V DDD-40 Period 1: Participants assigned to RV DDD-40 Participants will then Crossover to Period 2. Period 2: Participants assigned to VVI-40 Participants will then Crossover to Period 3. Period 3: Participants assigned to Bi-V DDD-40	Device: VVI-40; Pacing mode set to VVI-40, RV only pacing; Device: RV DDD-40; ICD programmed to DDD-40, RV only pacing with aan AV interval producing QRS fusion on surface EKG.; Device: BiV DDD-40; ICD programmed to BiV pacing at a lower rate of 40
Experimental: RV DDD-40 to Bi-V DDD-40 to VVI-40 Period 1: Participants assigned to RV DDD-40 Participants will then Crossover to Period 2. Period 2: Participants assigned to Bi-V DDD-40 Participants will then Crossover to Period 3. Period 3: Participants assigned to VVI-40	Device: VVI-40; Pacing mode set to VVI-40, RV only pacing; Device: RV DDD-40; ICD programmed to DDD-40, RV only pacing with aan AV interval producing QRS fusion on surface EKG.; Device: BiV DDD-40; ICD programmed to BiV pacing at a lower rate of 40

Outcome Measures

Primary Outcome Measures

1. The Primary Endpoint of the Trial Will be a Comparison of the Proportion of Patients in Each of the Three Treatment Groups Who Demonstrate Positive LV Remodeling, Defined as a Decrease in LV End Systolic Diameter of >5mm. [6 months]

Secondary Outcome Measures

1. Secondary Echocardiographic Endpoints [6 months]

   Comparisons of the derived velocity-time integral calculated on the aortic continuous wave Doppler-spectrogram, RV end-diastolic size, RV EF, mitral and tricuspid regurgitation severity, and estimated RV systolic pressure.

2. Arrhythmic Events [6 months]

   To determine if pacing mode impacts the frequency of ventricular arrhythmias, the incidence of ventricular tachyarrhythmia episodes on device interrogation will be compared between treatment group assignments. An episode will be considered ventricular arrhythmia if it lasts longer than 30 seconds or requires anti-tachycardia pacing or high voltage device therapy for termination.

3. Minnesota Quality of Life Questionnaire [6 months]

   This is a standardized method for assessing quality of life in patients with heart failure. It asks 21 questions and measures the impact HF has on a subject's life. Each question is rated 0-5. The total score for the 21 items can range from 0 to 105. Higher scores indicate more burden of disease on quality of life.

4. 6-minute Walk Distance [6 months]

   6-minute walk distance was the distance that a participant could walk in 6 minutes.

5. NYHA Function Class [6 months]

   The New York Heart Association (NYHA) Functional Classification places patients in one of four categories based on how much they are limited during physical activity. Class I means there is no limitation of physical activity and Class IV means a person is unable to carry on any physical activity without discomfort/symptoms of heart failure at rest.

6. Left Ventricular Ejection Fraction (LVEF) [6 months]

7. Left Ventricular End-diastolic Size [6 months]

Eligibility Criteria

Criteria

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

Inclusion Criteria:

• Cardiomyopathy of either idiopathic or ischemic etiology

• NYHA class III, or IV symptoms

• Sinus rhythm

• QRS complex duration > 130 msec in ≥ 2 surface ECG leads with RBBB

• PR interval > 150 msec and < 240 msec

• Prior implantation of dual chamber BiV ICD with apical RV lead location

Exclusion Criteria:

• Myocardial infarction, major surgical procedure, or acute cardiac failure crisis requiring inotropes within 6 months of entry into the study

• Atrial fibrillation or flutter lasting >12 hours within the last 6 months

• Sick sinus syndrome, complete heart block, or other arrhythmias requiring pacemaker support

• Pregnancy

• Any other known condition other than heart failure that could limit exercise time or survival to < 6 months

Contacts and Locations

Locations

	Site	City	State	Country	Postal Code
1	Duke University Medical Center	Durham	North Carolina	United States	27710
2	Durham VA Medical Center	Durham	North Carolina	United States	27710

Sponsors and Collaborators

• Duke University
• American Heart Association

Investigators

• Principal Investigator: Brett D Atwater, MD, Duke University

Study Documents (Full-Text)

None provided.

More Information

Publications

None provided.

• Responsible Party: Duke University
• ClinicalTrials.gov Identifier: NCT01169493
• Other Study ID Numbers: Pro00025144; 10CRP3630033
• First Posted: Jul 26, 2010
• Last Update Posted: Sep 23, 2016
• Last Verified: Aug 1, 2016

• Keywords provided by Duke University: Heart Failure; Right Bundle-Branch Block; Cardiac Resynchronization Therapy
• Additional relevant MeSH terms: Heart Failure; Bundle-Branch Block; Heart Block

Study Results

Participant Flow

Arm/Group Title	VVI-40 to RV DDD-40 to Bi-V DDD-40	VVI-40 to Bi-V DDD-40 to RV DDD-40	Bi-V DDD-40 to VVI-40 to RV DDD-40	Bi-V DDD-40 to RV DDD-40 to VVI-40	RV DDD-40 to VVI-40 to Bi-V DDD-40	RV DDD-40 to Bi-V DDD-40 to VVI-40
Arm/Group Description	Period 1: Participants assigned to VVI-40 Participants will then Crossover to Period 2. Period 2: Participants assigned to RV DDD-40 Participants will then Crossover to Period 3. Period 3: Participants assigned to Bi-V DDD-40 VVI-40: Pacing mode set to VVI-40, RV only pacing RV DDD-40: ICD programmed to DDD-40, RV only pacing with aan AV interval producing QRS fusion on surface EKG. BiV DDD-40: ICD programmed to BiV pacing at a lower rate of 40	Period 1: Participants assigned to VVI-40 Participants will then Crossover to Period 2. Period 2: Participants assigned to Bi-V DDD-40 Participants will then Crossover to Period 3. Period 3: Participants assigned to RV DDD-40 VVI-40: Pacing mode set to VVI-40, RV only pacing RV DDD-40: ICD programmed to DDD-40, RV only pacing with aan AV interval producing QRS fusion on surface EKG. BiV DDD-40: ICD programmed to BiV pacing at a lower rate of 40	Period 1: Participants assigned to Bi-V DDD-40 Participants will then Crossover to Period 2. Period 2: Participants assigned to VVI-40 Participants will then Crossover to Period 3. Period 3: Participants assigned to RV DDD-40 VVI-40: Pacing mode set to VVI-40, RV only pacing RV DDD-40: ICD programmed to DDD-40, RV only pacing with aan AV interval producing QRS fusion on surface EKG. BiV DDD-40: ICD programmed to BiV pacing at a lower rate of 40	Period 1: Participants assigned to Bi-V DDD-40 Participants will then Crossover to Period 2. Period 2: Participants assigned to RV DDD-40 Participants will then Crossover to Period 3. Period 3: Participants assigned to VVI-40 VVI-40: Pacing mode set to VVI-40, RV only pacing RV DDD-40: ICD programmed to DDD-40, RV only pacing with aan AV interval producing QRS fusion on surface EKG. BiV DDD-40: ICD programmed to BiV pacing at a lower rate of 40	Period 1: Participants assigned to RV DDD-40 Participants will then Crossover to Period 2. Period 2: Participants assigned to VVI-40 Participants will then Crossover to Period 3. Period 3: Participants assigned to Bi-V DDD-40 VVI-40: Pacing mode set to VVI-40, RV only pacing RV DDD-40: ICD programmed to DDD-40, RV only pacing with aan AV interval producing QRS fusion on surface EKG. BiV DDD-40: ICD programmed to BiV pacing at a lower rate of 40	Period 1: Participants assigned to RV DDD-40 Participants will then Crossover to Period 2. Period 2: Participants assigned to Bi-V DDD-40 Participants will then Crossover to Period 3. Period 3: Participants assigned to VVI-40 VVI-40: Pacing mode set to VVI-40, RV only pacing RV DDD-40: ICD programmed to DDD-40, RV only pacing with aan AV interval producing QRS fusion on surface EKG. BiV DDD-40: ICD programmed to BiV pacing at a lower rate of 40
Period Title: Period 1 (6 Months)
STARTED	2	4	5	0	0	5
COMPLETED	2	3	3	0	0	2
NOT COMPLETED	0	1	2	0	0	3
Period Title: Period 1 (6 Months)
STARTED	2	3	3	0	0	2
COMPLETED	2	3	3	0	0	2
NOT COMPLETED	0	0	0	0	0	0
Period Title: Period 1 (6 Months)
STARTED	2	3	3	0	0	2
COMPLETED	2	1	2	0	0	2
NOT COMPLETED	0	2	1	0	0	0

Baseline Characteristics

Arm/Group Title	VVI-40 to RV DDD-40 to Bi-V DDD-40	VVI-40 to Bi-V DDD-40 to RV DDD-40	Bi-V DDD-40 to VVI-40 to RV DDD-40	Bi-V DDD-40 to RV DDD-40 to VVI-40	RV DDD-40 to VVI-40 to Bi-V DDD-40	RV DDD-40 to Bi-V DDD-40 to VVI-40	Total
Arm/Group Description	Period 1: Participants assigned to VVI-40 Participants will then Crossover to Period 2. Period 2: Participants assigned to RV DDD-40 Participants will then Crossover to Period 3. Period 3: Participants assigned to Bi-V DDD-40 VVI-40: Pacing mode set to VVI-40, RV only pacing RV DDD-40: ICD programmed to DDD-40, RV only pacing with aan AV interval producing QRS fusion on surface EKG. BiV DDD-40: ICD programmed to BiV pacing at a lower rate of 40	Period 1: Participants assigned to VVI-40 Participants will then Crossover to Period 2. Period 2: Participants assigned to Bi-V DDD-40 Participants will then Crossover to Period 3. Period 3: Participants assigned to RV DDD-40 VVI-40: Pacing mode set to VVI-40, RV only pacing RV DDD-40: ICD programmed to DDD-40, RV only pacing with aan AV interval producing QRS fusion on surface EKG. BiV DDD-40: ICD programmed to BiV pacing at a lower rate of 40	Period 1: Participants assigned to Bi-V DDD-40 Participants will then Crossover to Period 2. Period 2: Participants assigned to VVI-40 Participants will then Crossover to Period 3. Period 3: Participants assigned to RV DDD-40 VVI-40: Pacing mode set to VVI-40, RV only pacing RV DDD-40: ICD programmed to DDD-40, RV only pacing with aan AV interval producing QRS fusion on surface EKG. BiV DDD-40: ICD programmed to BiV pacing at a lower rate of 40	Period 1: Participants assigned to Bi-V DDD-40 Participants will then Crossover to Period 2. Period 2: Participants assigned to RV DDD-40 Participants will then Crossover to Period 3. Period 3: Participants assigned to VVI-40 VVI-40: Pacing mode set to VVI-40, RV only pacing RV DDD-40: ICD programmed to DDD-40, RV only pacing with aan AV interval producing QRS fusion on surface EKG. BiV DDD-40: ICD programmed to BiV pacing at a lower rate of 40	Period 1: Participants assigned to RV DDD-40 Participants will then Crossover to Period 2. Period 2: Participants assigned to VVI-40 Participants will then Crossover to Period 3. Period 3: Participants assigned to Bi-V DDD-40 VVI-40: Pacing mode set to VVI-40, RV only pacing RV DDD-40: ICD programmed to DDD-40, RV only pacing with aan AV interval producing QRS fusion on surface EKG. BiV DDD-40: ICD programmed to BiV pacing at a lower rate of 40	Period 1: Participants assigned to RV DDD-40 Participants will then Crossover to Period 2. Period 2: Participants assigned to Bi-V DDD-40 Participants will then Crossover to Period 3. Period 3: Participants assigned to VVI-40 VVI-40: Pacing mode set to VVI-40, RV only pacing RV DDD-40: ICD programmed to DDD-40, RV only pacing with aan AV interval producing QRS fusion on surface EKG. BiV DDD-40: ICD programmed to BiV pacing at a lower rate of 40	Total of all reporting groups
Overall Participants	2	4	5	0	0	5	16
Age (participants) [Number]
<=18 years	0 0%	0 0%	0 0%	0 NaN	0 NaN
Between 18 and 65 years	0 0%	1 25%	0 0%	2 Infinity	3 Infinity
>=65 years	2 100%	3 75%	5 100%	3 Infinity	13 Infinity
Gender (participants) [Number]
Female	0 0%	0 0%	0 0%	0 NaN	0 NaN
Male	2 100%	4 100%	5 100%	5 Infinity	16 Infinity

Outcome Measures

1. Primary Outcome

Title	The Primary Endpoint of the Trial Will be a Comparison of the Proportion of Patients in Each of the Three Treatment Groups Who Demonstrate Positive LV Remodeling, Defined as a Decrease in LV End Systolic Diameter of >5mm.
Time Frame	6 months

Outcome Measure Data

Analysis Population Description

All participants who completed the six month period for VVI-40, RV DDD-40, Bi-V DDD-40 regardless of which arm they are randomized to. Participants may be counted as completing more than one period.

Arm/Group Title	VVI-40	RV DDD-40	Bi-V DDD-40
Arm/Group Description	The VVI-40 arm will be programmed to VVI (inhibited) mode at a lower rate of 40.	RV DDD-40 will have an AV interval set to produce QRS fusion with the native conduction down the native left bundle	Permits direct comparison of RV univentricular pacing and current standard of care (BiV) pacing.
Measure Participants	10	7	10
Number [percentage of participants]	0 0%	29 725%	20 400%

2. Secondary Outcome

Title	Secondary Echocardiographic Endpoints
Description	Comparisons of the derived velocity-time integral calculated on the aortic continuous wave Doppler-spectrogram, RV end-diastolic size, RV EF, mitral and tricuspid regurgitation severity, and estimated RV systolic pressure.
Time Frame	6 months

Outcome Measure Data

Analysis Population Description

Data not collected.

Arm/Group Title	VVI-40	RV DDD-40	Bi-V DDD-40
Arm/Group Description	The VVI-40 arm will be programmed to VVI (inhibited) mode at a lower rate of 40.	RV DDD-40 will have an AV interval set to produce QRS fusion with the native conduction down the native left bundle	Permits direct comparison of RV univentricular pacing and current standard of care (BiV) pacing.
Measure Participants	0	0	0

3. Secondary Outcome

Title	Arrhythmic Events
Description	To determine if pacing mode impacts the frequency of ventricular arrhythmias, the incidence of ventricular tachyarrhythmia episodes on device interrogation will be compared between treatment group assignments. An episode will be considered ventricular arrhythmia if it lasts longer than 30 seconds or requires anti-tachycardia pacing or high voltage device therapy for termination.
Time Frame	6 months

Outcome Measure Data

Analysis Population Description

All participants who completed the six month period for VVI-40, RV DDD-40, Bi-V DDD-40 regardless of which arm they are randomized to. Participants may be counted as completing more than one period.

Arm/Group Title	VVI-40	RV DDD-40	Bi-V DDD-40
Arm/Group Description	The VVI-40 arm will be programmed to VVI (inhibited) mode at a lower rate of 40.	RV DDD-40 will have an AV interval set to produce QRS fusion with the native conduction down the native left bundle	Permits direct comparison of RV univentricular pacing and current standard of care (BiV) pacing.
Measure Participants	10	7	10
Number [participants]	0 0%	0 0%	0 0%

4. Secondary Outcome

Title	Minnesota Quality of Life Questionnaire
Description	This is a standardized method for assessing quality of life in patients with heart failure. It asks 21 questions and measures the impact HF has on a subject's life. Each question is rated 0-5. The total score for the 21 items can range from 0 to 105. Higher scores indicate more burden of disease on quality of life.
Time Frame	6 months

Outcome Measure Data

Analysis Population Description

All participants who completed the six month period for VVI-40, RV DDD-40, Bi-V DDD-40 regardless of which arm they are randomized to. Participants may be counted as completing more than one period.

Arm/Group Title	VVI-40	RV DDD-40	Bi-V DDD-40
Arm/Group Description	The VVI-40 arm will be programmed to VVI (inhibited) mode at a lower rate of 40.	RV DDD-40 will have an AV interval set to produce QRS fusion with the native conduction down the native left bundle	Permits direct comparison of RV univentricular pacing and current standard of care (BiV) pacing.
Measure Participants	10	7	10
Mean (Standard Deviation) [units on a scale]	39.3 (21.3)	43.9 (20.3)	55.78 (27.7)

5. Secondary Outcome

Title	6-minute Walk Distance
Description	6-minute walk distance was the distance that a participant could walk in 6 minutes.
Time Frame	6 months

Outcome Measure Data

Analysis Population Description

All participants who completed the six month period for VVI-40, RV DDD-40, Bi-V DDD-40 regardless of which arm they are randomized to. Participants may be counted as completing more than one period.

Arm/Group Title	VVI-40	RV DDD-40	Bi-V DDD-40
Arm/Group Description	The VVI-40 arm will be programmed to VVI (inhibited) mode at a lower rate of 40.	RV DDD-40 will have an AV interval set to produce QRS fusion with the native conduction down the native left bundle	Permits direct comparison of RV univentricular pacing and current standard of care (BiV) pacing.
Measure Participants	10	7	10
Mean (Standard Deviation) [meters]	292.4 (70.5)	235.8 (122.8)	244.44 (122)

6. Secondary Outcome

Title	NYHA Function Class
Description	The New York Heart Association (NYHA) Functional Classification places patients in one of four categories based on how much they are limited during physical activity. Class I means there is no limitation of physical activity and Class IV means a person is unable to carry on any physical activity without discomfort/symptoms of heart failure at rest.
Time Frame	6 months

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	VVI-40	RV DDD-40	Bi-V DDD-40
Arm/Group Description	The VVI-40 arm will be programmed to VVI (inhibited) mode at a lower rate of 40.	RV DDD-40 will have an AV interval set to produce QRS fusion with the native conduction down the native left bundle	Permits direct comparison of RV univentricular pacing and current standard of care (BiV) pacing.
Measure Participants	10	7	10
Mean (Standard Deviation) [units on a scale]	3.3 (0.7)	3 (0.6)	3.2 (0.9)

7. Secondary Outcome

Title	Left Ventricular Ejection Fraction (LVEF)
Time Frame	6 months

Outcome Measure Data

Analysis Population Description

Data not collected.

Arm/Group Title	VVI-40	RV DDD-40	Bi-V DDD-40
Arm/Group Description	The VVI-40 arm will be programmed to VVI (inhibited) mode at a lower rate of 40.	RV DDD-40 will have an AV interval set to produce QRS fusion with the native conduction down the native left bundle	Permits direct comparison of RV univentricular pacing and current standard of care (BiV) pacing.
Measure Participants	10	7	10
Mean (Standard Deviation) [percent]	24.8 (7.4)	20 (9.7)	22.9 (7.7)

8. Secondary Outcome

Title	Left Ventricular End-diastolic Size
Time Frame	6 months

Outcome Measure Data

Analysis Population Description

Data not collected.

Arm/Group Title	VVI-40	RV DDD-40	Bi-V DDD-40
Arm/Group Description	The VVI-40 arm will be programmed to VVI (inhibited) mode at a lower rate of 40.	RV DDD-40 will have an AV interval set to produce QRS fusion with the native conduction down the native left bundle	Permits direct comparison of RV univentricular pacing and current standard of care (BiV) pacing.
Measure Participants	10	7	10
Mean (Standard Error) [cubic cm]	203 (39.9)	236.6 (27.1)	236.5 (54.6)

Adverse Events

Time Frame	Adverse event data was collected over 18 months
Arm/Group Title	VVI-40		RV DDD-40		Bi-V DDD-40
Arm/Group Description	VVI-40: Pacing mode set to VVI-40, RV only pacing		RV DDD-40: ICD programmed to DDD-40, RV only pacing with an AV interval producing QRS fusion on surface EKG.		Bi-V DDD-40: ICD programmed to Bi-V pacing at a lower rate of 40
All Cause Mortality
	VVI-40		RV DDD-40		Bi-V DDD-40
	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events
Total	/ (NaN)		/ (NaN)		/ (NaN)
Serious Adverse Events
	VVI-40		RV DDD-40		Bi-V DDD-40
	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events
Total	0/11 (0%)		0/13 (0%)		3/12 (25%)
Cardiac disorders
Heart Failure Exacerbation, Heart Transplant	0/11 (0%)	0	0/13 (0%)	0	2/12 (16.7%)	2
Death	0/11 (0%)	0	0/13 (0%)	0	1/12 (8.3%)	1
Infections and infestations
Death	0/11 (0%)	0	0/13 (0%)	0	0/12 (0%)	0
Other (Not Including Serious) Adverse Events
	VVI-40		RV DDD-40		Bi-V DDD-40
	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events
Total	0/11 (0%)		0/13 (0%)		0/12 (0%)

Limitations/Caveats

We were unable to enroll adequately, and the study was underpowered to assess either the safety or efficacy of RV only, or BIV pacing in patients with right bundle branch block.

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.