[Estimation of defibrillation threshold using abdominally implanted cardioverter-defibrillator with an additional...

Safety of patients treated with an implanted cardioverter-defibrillator (ICD) depends on defibrillator threshold (DFT). In patients with frequent ICD interventions the high DFT influences battery life-time. The aim of the study was to compare DFT in abdominally placed ICD with an active and passive can and dual-coil endocardial leads.

The study involved 9 patients (4 F and 5 M, mean age 56 +/- 19 years) with previously implanted in abdominal position ICD with passive can and dual-coil defibrillation lead. In all patients DFT was measured using active and passive can ICD at the time of planed generator replacement.

Compared to the passive can, the abdominal active can ICD lowered DFT in 6 patients (66%), in 1 patients the DFT increased, whereas in 2 patients we observed no change in DFT. The mean DFT measured with the passive can ICD was 11.6 +/- 5.2J (5.1-20J) and with the active can was 9,3 +/- 4,5J (3-18J). The mean defibrillation resistance was 64 +/- 11W (48-84W) and 55 +/- 8W (47-70W) in passive and active can respectively. Active can ICD decreased the DFT by 20% (p = 0.049) and the defibrillation resistance by 23% (p = 0.012).

An abdominally positioned active can ICD with dual coil defibrillation leads allowed to lower DFT and defibrillation resistance in a majority of patients. It seems useful to replace previously implanted passive can ICDs with an active ones particularly in patients with high DFT.