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

Cardiomyopathy Clinical Trial

— VF  

Official title:

Comparison of Ventricular Fibrillation Induction Techniques During Medtronic Implantable Cardioverter Defibrillator Implant

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT02027883
• Other study ID #: VF Induction
• Status: Completed
• Phase: N/A
• Start date: January 2011
• Est. completion date: August 2012

Study information

• Verified date: April 2018
• Source: Wellmont CVA Heart Institute
• Contact: n/a
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial 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.

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.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 100
• Est. completion date: August 2012
• Est. primary completion date: August 2012
• Accepts healthy volunteers: No
• Gender: All
• Age group: 18 Years and older

Eligibility

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.

Related Conditions & MeSH terms

• Cardiomyopathies
• Cardiomyopathy
• Ventricular Fibrillation

Intervention

Device:
• Nominal T shock setting
Nominal Parameter Set 1 Programming Values for EnTrust
• Educated T shock setting
Experimental Parameter Set 2 Programming Values

Locations

Country	Name	City	State
United States	Wellmont CVA Heart Institute	Kingsport	Tennessee

Sponsors (2)

Lead Sponsor	Collaborator
James Merrill	Medtronic

Country where clinical trial is conducted

United States, 

References & Publications (5)

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. — View Citation

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.

Outcome

Type	Measure	Description	Time frame	Safety issue
Other	Safety Monitoring	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.	2 hours
Primary	Sustained Ventricular Fibrillation	The primary endpoint is the successful induction of sustained ventricular fibrillation.	2 hours
Secondary	Factors	Determine if any pre-implant patient demographics are factors impacting T-shock success according to parameter settings.	2 hours