An abdominal active can defibrillator may facilitate a successful generator change when a lead failure is present

Aims Defibrillator generator changes are frequently performed on patients w ith an implantable cardioverter defibrillator in an abdominal pocket. These patients usually have epicardial patches or older endocardial lead systems . At the time of a defibrillator generator change defibrillation may be uns uccessful as a result of lead failure. We tested the hypothesis that an act ive can defibrillator implanted in the abdominal pocket could replace a nun -functioning endocardial lead or epicardial patch. Methods and Results An abdominal defibrillator generator change was perform ed in 10 patients, (mean age= 67 +/- 13 years, nine men). Initially, a defi brillation threshold (DFT) was obtained using a passive defibrillator and t he chronic endocardial or epicardial lead system. DFTs were then performed using an active can emulator and one chronic lead to simulate endocardial o r epicardial lead failure. We tested 30 lead configurations (nine endocardi al and 21 epicardial). Although a DFT of 7.3 +/- 4.2 joules was obtained wi th the intact chronic lead system, the active can emulator and one endocard ial or epicardial lead still yielded an acceptable DFT of 19.9 +/- 6.1 joul es. In addition, a successful implant (DFT less than or equal to 24 joules) could have been accomplished in 28 of 30 (93%) lead configurations. Conclusion An active can defibrillator in an abdominal pocket may allow for a successful generator change in patients with defibrillator lead malfunct ion. This would be simpler than abandoning the abdominal implant and moving to a new pectoral device and lead or tunnelling a new endocardial electrod e. However, loss of defibrillation capability with a particular complex lea d may be a warning of impending loss of other functions (eg. sensing and/or pacing). (C) 1999 The European Society of Cardiology.