Implantation of transvenous nonthoracotomy cardioverter-defibrillator systems in patients with permanent endocardial pacemakers

Among 177 patients in whom a nonthoracotomy approach was initially used to implant a cardioverter-defibrillator system, 11 (6%) patients also received a separately implanted permanent pacemaker. The main problem encountered in these patients were previously implanted unipolar pacemakers ( n = 3) and ventricular pacing leads positioned at the right ventricular apex, the latter interfering with optimal placement of the tripolar implantable cardioverter-defibrillator (ICD) lead ( n = 9). The approaches used to solve these problems were individualized and included placement of the ICD sensing lead at the right ventricular outflow tract ( n = 3), initial placement ( n = 1) or subsequent repositioning ( n = 2) of the right ventricular pacing lead at the outflow tract, upgrade from unipolar to bipolar systems ( n = 2), reprogramming from the DDD to AAI mode ( n = 2), inactivation of the pacemaker ( n = 1), and simultaneous placement of a single-chamber atrial pacemaker with the ICD lead ( n = 2). These revisions fulfilled the pacing needs in each patient and prevented unfavorable sensing interaction between the two systems.