Study of Defibrillation Testing In Patients Undergoing Initial ICD Implantation (TNT-ICD)

The primary objective of this study is to compare the composite outcome of total mortality and operative complications in patients who do not undergo defibrillation testing to those who do undergo defibrillation testing at the time of initial ICD implantation.

Implantable cardioverter-defibrillators (ICDs) are the most effective treatment for the primary and secondary prevention of sudden cardiac death (SCD). At the time of ICD implantation, ventricular fibrillation (VF) is typically induced to demonstrate effective arrhythmia termination by the implanted device. Although defibrillation threshold (DFT) testing with induction of VF at time of ICD insertion is currently considered the "standard of care," and instructions for usage of devices approved by the Food and Drug Administration (FDA) include labeling with DFT testing, the value of defibrillation testing with modern-day devices has been questioned. Defibrillation testing can be associated with serious complications and may add to the cost of the procedure. It is hypothesized that patients who do not undergo defibrillation testing will have outcomes similar to those who do undergo defibrillation testing at the time of initial implantation. This pilot study is being performed to determine the feasibility of performing a larger, multi-center clinical trial with longer follow-up to investigate whether or not defibrillation testing will have any impact on overall mortality, implant complications, or long-term first shock efficacy during clinical follow-up.

The composite endpoint of implant complications and mortality rates will be compared in the DFT vs. no DFT groups.

Procedure-related complications will be defined as those occurring within 90 days post-implantation and mortality will be measured at 2 year follow-up

Inclusion Criteria: Age ≥ 18 years Initial ICD implantation (single, dual, or CRT) for a standard Class I or Class II indication according to the ACC/AHA/HRS practice guidelines Anticipated life expectancy >6 months Exclusion Criteria: Contraindications to defibrillation testing as determined by the managing physician* ICD replacement implants Right-sided pectoral implants Abdominal implants Chronic oral amiodarone therapy (for >6 weeks and continued need for amiodarone) Inability to give informed consent Contraindications to defibrillation testing include the following: hemodynamic instability, LA thrombus, atrial fibrillation without adequate anticoagulation, LV thrombus, recent CVA or TIA, severe unrevascularized coronary artery disease or unstable angina, severe aortic stenosis, inotropic dependence, patient refusal, other patient-specific medical conditions that are deemed as contraindications, as determined by the implanting physician.

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