Comparison of VF Induction Techniques During Medtronic ICD Implant (VF) (ICD)

• Sponsor: James Merrill (Other)
• Overall Status: Completed
• CT.gov ID: NCT02027883
• Collaborator: Medtronic (Industry)
• Enrollment: 100
• Location: 1
• Arms: 2
• Duration (Months): 19
• Patients Per Site Per Month: 5.3

Study Details

Study Description

Brief Summary

As the indications for Implantable Cardioverter Defibrillator implantation expand, minimizing implant time is critical. Also, patients receiving biventricular ICDs are sometimes more unstable and minimization of sedation time is crucial. Multiple induction attempts, with a 1-Joule shock, can cause disruption in lead position. Therefore limiting the number of attempts will allow for better lead stability throughout the procedure and a more straightforward implant process.

Investigator proposes a detailed documentation of success rates from various Ventriculart Fibrillation induction methods during implant of Medtronic defibrillation capable devices.

Condition or Disease	Intervention/Treatment	Phase
Cardiomyopathy	Device: Nominal T shock setting; Device: Educated T shock setting	N/A

Detailed Description

Our clinical experience has found that attempts to induce patients receiving ICDs at implant using the nominal Medtronic T-shock settings are not always effective at inducing ventricular fibrillation. When this results, a change to the parameters for T-shock is made before reattempting to induce ventricular fibrillation in patients undergoing ICD implantation.

Another available induction method is 50 Hz Burst. "The 50 Hz Burst induction is designed to induce VF by delivering a rapid burst of pacing pulses. The amplitude and pulse width of these pulses are selectable, but the pacing interval is fixed at 20 ms."2 If multiple attempts using the T-shock method are unsuccessful, 50 Hz Burst provides an additional method for inducing ventricular fibrillation. It is a less desirable method since it can result in very fine VF that is difficult to identify the initiation of possibly resulting in longer times in VF causing higher defibrillation threshold or in undersensing due to the fine nature of the rhythm.

T-shock has been found to be a fast and reliable method for inducing ventricular fibrillation in ICD implants. Greater success of inducing ventricular fibrillation using the T-shock method has been found when the energy of the T-shock was higher and the coupling interval was shorter. In addition, increasing the shock strength increases the window of vulnerability. For the T-shock method to be most efficient, initial success at inducing ventricular fibrillation, and therefore a reduced number of attempts, is important. This requires a better understanding of the optimal programmed settings for the initial T-shock induction attempt.

Moreover, in recent years, ICD indications have grown to include primary prevention patients. These patients may have different vulnerable periods than patients previously evaluated to develop Medtronic nominal settings.

Our clinical experience has found that the nominal T-shock settings are only effective at inducing ventricular fibrillation approximately seventy-five percent of the time. However, a detailed collection of success rates has not been performed.

Study Design

• Study Type: Interventional
• Actual Enrollment: 100 participants
• Allocation: Randomized
• Intervention Model: Parallel Assignment
• Masking: None (Open Label)
• Primary Purpose: Treatment
• Official Title: Comparison of Ventricular Fibrillation Induction Techniques During Medtronic Implantable Cardioverter Defibrillator Implant
• Study Start Date: Jan 1, 2011
• Actual Primary Completion Date: Aug 1, 2012
• Actual Study Completion Date: Aug 1, 2012

Arms and Interventions

Arm	Intervention/Treatment
Active Comparator: Nominal Parameter Nominal T shock setting	Device: Nominal T shock setting; Nominal Parameter Set 1 Programming Values for EnTrust; Other Names: Medtronic ICDs
Experimental: Experimental Parameter Educated T shock setting	Device: Educated T shock setting; Experimental Parameter Set 2 Programming Values; Other Names: Medtronic ICDs

Outcome Measures

Primary Outcome Measures

1. Sustained Ventricular Fibrillation [2 hours]

   The primary endpoint is the successful induction of sustained ventricular fibrillation.

Secondary Outcome Measures

1. Factors [2 hours]

   Determine if any pre-implant patient demographics are factors impacting T-shock success according to parameter settings.

Other Outcome Measures

1. Safety Monitoring [2 hours]

   Number of participants that were monitored for safety issues, including increased heart rate, blood pressure, decreased oximetry levels, and stable rhythm during the entire procedure.

Eligibility Criteria

Criteria

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

Inclusion Criteria:

• All patients undergoing Medtronic ICD or Cardiac Resynchronization Therapy-Defibrillator implant (initial implant or generator replacement) will be included.

Exclusion Criteria:

• Any patient who is medically unstable and testing is deemed unsafe by physician will be excluded from this study.

Contacts and Locations

Locations

	Site	City	State	Country	Postal Code
1	Wellmont CVA Heart Institute	Kingsport	Tennessee	United States	37660

Sponsors and Collaborators

• James Merrill
• Medtronic

Investigators

None specified.

Study Documents (Full-Text)

None provided.

More Information

Publications

• Bardy G, Mehra R, Johnson G, Kudenchuk P, Dolack G, Poole J, Hofer B: Low energy pulsing on the T-wave: A new programming method for intentional, device mediated induction of ventricular fibrillation for defibrillation testing. PACE 15(4, Pt II): 562, 1992.
• Bhandari AK, Isber N, Estioko M, Ziccardi T, Cannom DS, Park Y, Lerman RD, Prejean C, Sun GW. Efficacy of low-energy T wave shocks for induction of ventricular fibrillation in patients with implantable cardioverter defibrillators. J Electrocardiol. 1998 Jan;31(1):31-7.
• Marquis DR Reference Manual, Medtronic, Inc.
• Mitchell L, Yee R, Talajic M, Newman D, Sheldon R, Kerr C, Kus T, Boyle A, Canadian Jewel PCD Investigators: Low-energy, T-wave synchronous, interval shock for rapid, reliable ventricular fibrillation induction by an implantable cardioverter defibrllattor. PACE, 17(4, Pt II): 851, 1994.
• Swartz J, Stanton M, DeGroot P, Mehra R: Influence of T-wave shock energy on ventricular fibrillation vulnerability in humans. JACC 1995 Conference Abstracts: 214A, 1995.

• Responsible Party: James Merrill, James Merrill, MD, FACC, Wellmont CVA Heart Institute
• ClinicalTrials.gov Identifier: NCT02027883
• Other Study ID Numbers: VF Induction
• First Posted: Jan 6, 2014
• Last Update Posted: May 22, 2018
• Last Verified: Apr 1, 2018

• Individual Participant Data (IPD) Sharing Statement: No
• Plan to Share IPD: No
• Keywords provided by James Merrill, James Merrill, MD, FACC, Wellmont CVA Heart Institute: Defibrillators; Ventricular Fibrillation Induction Testing
• Additional relevant MeSH terms: Cardiomyopathies; Ventricular Fibrillation

Study Results

Participant Flow

Arm/Group Title	Nominal Parameter	Experimental Parameter
Arm/Group Description	Nominal T shock setting Nominal T shock setting: Nominal Parameter Set 1 Programming Values for EnTrust	Educated T shock setting Educated T shock setting: Experimental Parameter Set 2 Programming Values
Period Title: Overall Study
STARTED	50	50
COMPLETED	50	50
NOT COMPLETED	0	0

Baseline Characteristics

Arm/Group Title	Nominal Parameter	Experimental Parameter	Total
Arm/Group Description	Nominal T shock setting Nominal T shock setting: Nominal Parameter Set 1 Programming Values for EnTrust	Educated T shock setting Educated T shock setting: Experimental Parameter Set 2 Programming Values	Total of all reporting groups
Overall Participants	50	50	100
Age (Count of Participants)
<=18 years	0 0%	0 0%	0 0%
Between 18 and 65 years	27 54%	18 36%	45 45%
>=65 years	23 46%	32 64%	55 55%
Age (years) [Mean (Standard Deviation) ]
Mean (Standard Deviation) [years]	61.82 (13.68403)	66.68 (10.51809)	64.25 (12.38554)
Sex: Female, Male (Count of Participants)
Female	12 24%	10 20%	22 22%
Male	38 76%	40 80%	78 78%
Ethnicity (NIH/OMB) (Count of Participants)
Hispanic or Latino	0 0%	0 0%	0 0%
Not Hispanic or Latino	50 100%	50 100%	100 100%
Unknown or Not Reported	0 0%	0 0%	0 0%
Race (NIH/OMB) (Count of Participants)
American Indian or Alaska Native	0 0%	0 0%	0 0%
Asian	0 0%	0 0%	0 0%
Native Hawaiian or Other Pacific Islander	0 0%	0 0%	0 0%
Black or African American	0 0%	0 0%	0 0%
White	50 100%	50 100%	100 100%
More than one race	0 0%	0 0%	0 0%
Unknown or Not Reported	0 0%	0 0%	0 0%
Region of Enrollment (participants) [Number]
United States	50 100%	50 100%	100 100%
VF Induction amount of participants (participants) [Number]
Number [participants]	50 100%	50 100%	100 100%

Outcome Measures

1. Primary Outcome

Title	Sustained Ventricular Fibrillation
Description	The primary endpoint is the successful induction of sustained ventricular fibrillation.
Time Frame	2 hours

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Nominal Parameter	Experimental Parameter
Arm/Group Description	Nominal T shock setting Nominal T shock setting: Nominal Parameter Set 1 Programming Values for EnTrust	Educated T shock setting Educated T shock setting: Experimental Parameter Set 2 Programming Values
Measure Participants	50	50
Number [participants]	38 76%	35 70%

2. Secondary Outcome

Title	Factors
Description	Determine if any pre-implant patient demographics are factors impacting T-shock success according to parameter settings.
Time Frame	2 hours

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Nominal Parameter	Experimental Parameter
Arm/Group Description	Nominal T shock setting: Nominal Parameter Set 1 Programming Values for EnTrust.	Educated T shock setting: Experimental Parameter Set 2 Programming Values.
Measure Participants	50	50
Successful Male Participants	30 60%	28 56%
Successful Female participants	8 16%	7 14%
Unsuccessful Male Participants	8 16%	12 24%
Unsuccessful Female Participants	4 8%	3 6%

3. Other Pre-specified Outcome

Title	Safety Monitoring
Description	Number of participants that were monitored for safety issues, including increased heart rate, blood pressure, decreased oximetry levels, and stable rhythm during the entire procedure.
Time Frame	2 hours

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Nominal Parameter	Experimental Parameter
Arm/Group Description	Nominal T shock setting Nominal T shock setting: Nominal Parameter Set 1 Programming Values for EnTrust The standard T-Shock method was successful in 76% of the patients. 38 out of 50 patients Ventricular Fibrillation was induced with the nominal T shock method. In contrast, 87 % or 13 out of 15 that failed to induce Ventricular Fibrillation using the educated T-Shock method was successfully induced when crossed to the nominal T-shock method.	Educated T shock setting Educated T shock setting: Experimental Parameter Set 2 Programming Values The educated T shock setting method was successful in 70% of the patients. 35 out of 50 patients Ventricular Fibrillation was induced with the educated T- shock method. Of the 12 patients that were did not have Ventricular fibrillation induced with the nominal T-shock method, they were all successfully induced with the educated T-Shock method.
Measure Participants	50	50
Number [participants]	50 100%	50 100%

Adverse Events

Time Frame	The patient's were observed for adverse events from the time of consent to the time they met the primary endpoint.
Arm/Group Title	Nominal Parameter		Experimental Parameter
Arm/Group Description	Nominal T shock setting Nominal T shock setting: Nominal Parameter Set 1 Programming Values for EnTrust		Educated T shock setting Educated T shock setting: Experimental Parameter Set 2 Programming Values
All Cause Mortality
	Nominal Parameter		Experimental Parameter
	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events
Total	/ (NaN)		/ (NaN)
Serious Adverse Events
	Nominal Parameter		Experimental Parameter
	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events
Total	0/50 (0%)		0/50 (0%)
Other (Not Including Serious) Adverse Events
	Nominal Parameter		Experimental Parameter
	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events
Total	0/50 (0%)		0/50 (0%)

Limitations/Caveats

[Not Specified]

More Information

Certain Agreements

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