COMBINED THERAPY WITH TRANSVENOUS IMPLANT ABLE CARDIOVERTER DEFIBRILLATOR AND PERMANENT PACEMAKER SYSTEMS/

Implantable cardioverter/defibrillators (ICD) represent in many patien ts with ventricular tachyarrhythmias the first line treatment. Up to 1 5 % of the patients requiring an ICD need concomitant permanent cardia c pacing for bradyarrhythmias resulting in the need of simultaneous IC D- and antibradycardic pacemaker-therapy. We present four patients wit h successful implantation of a transvenous ICD-system (Medtronic Jewel 7220 and Micro Jewel 7221; electrode: Medtronic 6939), all of which h ad an antibradycardic pacemaker (2 unipolar, 2 bipolar) implanted prio r to ICD-implantation. Meticulous intraoperative testing in order to a void adverse interactions between the two systems has been carried out successfully in all cases. Possible adverse interactions comprise ove rsensing of pacemaker signals by the ICD with subsequent inadequate th erapy, inhibition of defibrillation therapy during ventricular fibrill ation caused by false detection of pacemaker spikes by the ICD as well as reprogramming of the pacemaker after shock delivery. A review of t he published literature yielded 91 reported cases of combined ICD- and pacemaker-therapy. In 16 % of the patients, one or more of the mentio ned complications have been observed. Those occurred more frequently w ith unipolar than with bipolar pacemaker-systems. Thus, combined thera py with antibradycardic pacemaker and transvenous ICD-systems can be p erformed safely.