1026-85 Enhanced Defibrillation Efficacy with an Active Pectoral Pulse Generator

An active pectoral pulse generator can be incorporated in a single coil defibrillation lead system to achieve low defibrillation thresholds (DFT). However, the incremental benefit of an active pulse generator with an integrated lead system has not been evaluated. Accordingly, we performed a prospective trial of a 65 cc pulse generator shell with an Endotak lead in 22 consecutive pts undergoing defibrillator implantation. Energy (E) and leading edge voltage (V) at DFT was measured using a step down protocol to first failure with biphasic waveforms (60:40 tilt). Either lead alone (proximal coil=anode) or lead+shell (proximal coil and shell=anode) were tested with paired testing in random order.E(joules)V(volts)R(ohms)Lead alone13.1±6.7395±10549±5Lead+Shell8.5±3.1*319±61*42±4**p<0.001A DFT of≤10J was found in 50% (11/22) of patients with lead alone and 86% (19/22) of patients with lead+shell (p<0.02)In conclusionadding an active pulse generator to an integrated transvenous lead significantly reduced DFTs and system impedance (R). The consistently low defibrillation energy requirements with the use of an active small pectoral shell, makes the development of a defibrillator with reduced size and lower maximal output feasible