[Combined therapy with transvenous cardioverter/defibrillator and anti-bradycardia pacemaker systems]

Implantable cardioverter/ defibrillators (ICD) represent in many patients with ventricular tachyarrhythmias the first line treatment. Up to 15% of the patients requiring an ICD need concomitant permanent cardiac pacing for bradyarrhythmias resulting in the need of simultaneous ICD- and antibradycardic pacemaker-therapy. We present four patients with successful implantation of a transvenous ICD-system (Medtronic Jewel 7220 and Micro Jewel 7221; electrode: Medtronic 6939), all of which had an antibradycardic pacemaker (2 unipolar, 2 bipolar) implanted prior to ICD-implantation. Meticulous intraoperative testing in order to avoid adverse interactions between the two systems has been carried out successfully in all cases. Possible adverse interactions comprise oversensing of pacemaker signals by the ICD with subsequent inadequate therapy, inhibition of defibrillation therapy during ventricular fibrillation caused by false detection of pacemaker spikes by the ICD as well as reprogramming of the pacemaker after shock delivery. A review of the published literature yielded 91 reported cases of combined ICD- and pacemaker-therapy. In 16% of the patients, one or more of the mentioned complications have been observed. Those occurred more frequently with unipolar than with bipolar pacemaker-systems. Thus, combined therapy with antibradycardic pacemaker and transvenous ICD-systems can be performed safely.