Ninety-four patients underwent surgery for automatic implantable cardioverter-defibrillator implantation. Ninety patients were discharged from the hospital with the device and were followed up for a mean period of 17 +/- 10 months. Forty-six patients experienced at least one discharge of the device under circumstances consistent with a malignant ventricular arrhythmia. One sudden death occurred. Complications included perioperative death (3 patients), post-operative ventricular tachycardia (12 patients) and atrial fibrillation (8 patients), perioperative myocardial infarction (1 patient) and device discharges for sinus tachycardia and supraventricular arrhythmias (17 patients). Six and 12 month survival rates by life table analysis were 98.7 and 95.4%, respectively. Thus, the automatic implantable cardioverter-defibrillator is a highly effective and relatively low risk treatment modality for patients with refractory life-threatening ventricular arrhythmias.