Clinical experience, complications, and survival in 70 patients with the automatic implantable cardioverter/defibrillator.

Seventy patients received the automatic implantable defibrillator, five original devices and 72 modified second-generation devices using only bipolar rate sensing and delivering an R wave synchronous cardioverting/defibrillating shock, for either ventricular tachycardia or fibrillation. The primary clinical arrhythmia was sustained ventricular tachycardia in 32 patients, ventricular fibrillation in 20 patients, and both ventricular tachycardia and fibrillation in 18 patients. Before implantation of the device the patients had survived 3.1 +/- 2.3 arrhythmic episodes, including 1.9 +/- 1.7 cardiac arrest, and had received 4.0 +/- 2.1 antiarrhythmic drugs without improvement. Sixty-eight patients ultimately received devices. After a follow-up period of 8.9 +/- 7.7 months (range 1 to 33), 37 patients received a total of 463 discharges. Inability to determine the precise reason for most discharges and the unpleasant nature of the discharges were the major clinical problems encountered. Complications included ...