THE COMBINED TRANSVENOUS IMPLANTATION OF CARDIOVERTER-DEFIBRILLATORS AND PERMANENT PACEMAKERS

We developed criteria for implantation and programming of permanent en docardial pacemakers in patients with a nonthoracotomy ICD system. The se criteria were prospectively used in 10 patients who recieved an ICD prior to (n = 5) or following (n = 5) implantation of a dual chamber (n = 6) or ventricular (n = 4) pacemaker with a unipolar (n = 4) or bi polar (n = 6) lead configuration. All patients were tested for interac tions or malfunctions. Undersensing of ventricular fibrillation by the atrial sense amplifier and inadequate atrial pacing occurred in one p atient with a unipolar dual chamber system programmed to AAIR but didn 't impair ICD sensing. Transient or permanent loss of capture or sensi ng of the pacemaker wets not observed after ICD shocks with the output programmed to double pulse width and voltage of stimulation threshold and the sensitivity to 50% of the detected R wave. One episode of tra nsient reprogramming occurred without clinical consequences. One unipo lar ventricular pacemaker lead had to be exchanged against a bipolar l ead because of oversensing of the pacing artifact by the ICD. There wa s no failure of an ICD to detect ventricular arrhythmias due to inadeq uate pacemaker activity. During a follow-up period of 21 +/- 11 months , a total of 78 ventricular arrhythmias were effectively treated in si x patients. Thus, a combined use of transvenous ICD and pacemaker is p ossible despite the close vicinity of pacing and defibrillations leads . Optimized programming different to the common settings is required. As interactions occurred only in unipolar pacemaker leads bipolar syst ems should be used in these patients.