Dual-coil vs single-coil active pectoral implantable defibrillator lead systems: defibrillation energy requirements and probability of defibrillationsuccess at multiples of the defibrillation energy requirements

Aims The aim of the study was to compare the defibrillation energy requirem ents and the probability of successful defibrillation at multiples of tile minimum defibrillation energy requirements in active pectoral implantable d efibrillators with single- and dual-coil lead systems. Methods and Results Eighty-three consecutive patients undergoing implantati on of an active pectoral cardioverter-defibrillator were randomized to rece ive a dual- or single-coil load system. Defibrillators of two manufacturers with a fixed tilt biphasic defibrillation waveform were used. Defibrillati on energy requirements were determined using a step-down defibrillation tes ting protocol. According to the randomization protocol, the patients were a ssigned to three additional consecutive defibrillation attempts during devi ce implantation and during pre-discharge testing of either 1(.)0, 1(.)5 or 2(.)0 times the determined defibrillation energy requirement. patients pres enting defibrillation energy requirements > 15J were excluded From analysis . Eighty of 83 patients (96%) completed the study protocol. Three patients were excluded due to elevated defibrillation energy requirements. The defib rillation energy requirements in the dual- and single-coil patient groups w ere 8(.)0 +/- 3(.)6 J and 8(.)4 +/- 3(.)7 J (ns), respectively. A comparabl e percentage of study patients showed defibrillation energy requirements < 10 J (dual-coil: 88% vs single-coil: 83%). Defibrillation impedance was sig nificantly different (dual-coil: 50 +/-5(.)8 Ohm; single-coil: 39(.)8 +/-4( .)2 Ohm). Regarding the probabilities of successful defibrillation, there w ere no significant differences between the two patient groups. The probabil ities of defibrillation at the three multiples of the defibrillation energy requirement using a dual- and single-coil lead system were 82, 89(.)7 and 93(.)6 and 77(.)8, 94(.)1 and 95(.)8%, respectively (P=0(.)88, P=0(.)42, P= 0(.)62, respectively). Conclusions Dual- and single-coil active pectoral defibrillator systems sho w no difference in defibrillation energy requirements and no difference in the probability of successful defibrillation at multiples of the minimum de fibrillation energy requirement. The use of more simplified defibrillator l ead systems may contribute to a future lead design focusing on improvement in lead durability. (C) 2001 The European Society of Cardiology.