The authors present a retrospective and longitudinal study of the predictive factors of mortality in patients having an implanted automatic defibrillator. The population comprised 127 patients implanted between September 1988 and September 1997. There were 107 men with a mean age of 57.7 +/- 13 years. The left ventricular ejection fraction was 39.3%. The proportion of coronary patients was 68%; 20% of patients had atrial fibrillation and 5% were in Class III of the NYHA classification. The indications were: resuscitated cardiac arrest (N = 56) and poorly tolerated ventricular tachycardia (N = 71). The follow-up period was 30 +/- 25 months. There were 23 early and 10 late complications. Seventy-two patients had received an electric shock; 57 had an appropriate shock. There were 23 arrhythmic storms (ventricular arrhythmia requiring at least 2 shocks in less than 24 hours) in 17 patients. The operative mortality was 1.1%; at 1 year, the global survival was 93.9 +/- 2.2%; cardiac survival was 94.7 +/- 2.1%; survival without sudden death was 98.3 +/- 1.2%. Multivariate analysis isolated predictive factors for mortality; atrial fibrillation was predictive for global mortality; an ejection fraction < 30% and the fact of having received an appropriate shock were predictive of cardiac mortality; and an arrhythmic storm was predictive of sudden death.