Initial clinical experience with the pacemaker-cardioverter-defibrillator.

The implantation of a new multiprogrammable pacemaker-cardioverter-defibrillator is reported in four patients suffering from drug-refractory ventricular tachycardia or fibrillation. The generator (PCD 7215; Medtronic Inc) was interfaced to the epicardium by three countershock patch electrodes and one ventricular myocardial screw-in lead for sensing/pacing. The device employs separate rate detection criteria for ventricular tachycardia and ventricular fibrillation with automatic delivery of up to four therapies per episode. Therapeutic options include: antitachycardia burst or autodecremental pacing, synchronized cardioversion, defibrillation and ventricular demand pacing at 30 to 90 beats/min. Four men and one woman (ages 29 to 75 years) underwent intraoperative implant evaluation, and the device was implanted in the four men. Over a follow-up of 1.5 to 23 months, 161 spontaneous episodes of ventricular tachycardia and nine episodes meeting ventricular fibrillation criteria (cycle length less than 280 to 290 ms) were detected and treated by the device. Ramp pacing was initially employed to terminate 140 ventricular tachycardia episodes and was successful 88.5% of the time while 10 (7.2%) required low energy epicardial cardioversion (4 to 10 J). Six (4.3%) episodes terminated spontaneously prior to therapy delivery. All nine spontaneous episodes of ventricular fibrillation were defibrillated using 10 to 15 J. Two patients continue to do well with the device functioning reliably. The device was removed at the time of heart transplant in one patient, while another patient died suddenly from drug overdose. No other complications, device malfunctions or inappropriate therapy delivery have been observed. These early results demonstrate the potential usefulness of a programmable device which provides graded therapy for ventricular tachycardia with added defibrillation and bradycardia pacing capability.