The primary safety endpoint is Incidence of Adverse Device Effects (ADEs). The primary performance endpoint is Induced VF conversion success with ≥ 10J safety margin at 6 weeks. Secondary endpoints include pacing capture threshold, pacing impedance, R-wave amplitudes and sensation level while pacing.~Up to 30 eligible Subjects undergoing a pectoral transvenous ICD procedure (de novo or replacement) will receive an EV-ICD Lead connected to a commercially available ICD in a left mid-axillary pocket.~The EV-ICD System will be tested acutely to determine the lowest defibrillation energy. Subjects will remain in the hospital overnight minimum, prior to discharge. Before discharge, the EV-ICD will be programmed to monitor only (therapy OFF) to detect and store ventricular arrhythmias over the follow-up period. Other non-therapy programming parameters will match the transvenous ICD to the extent possible.~Follow-up visits are planned at 2 weeks (Day 11 to 17) and 6 weeks (Day 35 to 45). VF conversion testing will occur again at the 6-week visit to determine if a ≥10J safety margin exists.~The EV-ICD System will be removed on completion of the 6-week visit, leaving the transvenous ICD system in place. A post-removal follow-up to assess any post-removal adverse events will occur 25-35 days post-removal, prior to study exit.
STEP ICD is a premarket, exploratory, early feasibility, interventional study designed to evaluate early safety and performance of the Investigational Devices. The study is intended to inform the final device design which will be further evaluated in traditional feasibility and /or pivotal clinical investigations. Safety will be characterized through analysis of all adverse events through 6 weeks post-implant and 30 days post-explant. VF sensing and conversion of induced VF with the EV-ICD Lead over a 6 week implant period will be evaluated. Pacing and subject sensation while pacing will also be evaluated over the study period.