To determine the efficacy of left ventricular (LV) aneurysm resection and endoventricular patch repair with septal exclusion in patients with severely depressed pump function, we retrospectively selected 62 patients (mean age 59 +/- 7 years) with preoperative LV ejection fraction < or = 20%, from a series of 322 patients with postinfarction LV aneurysm who underwent this type of surgery at our center during a 5-year period. Mean ejection fraction was 17 +/- 3%; all patients were in New York Heart Association (NYHA) class III/IV, and all had hemodynamic and electrophysiologic studies before and after surgery. We analyzed both operative and long-term survival, and hemodynamic, electrophysiologic, and angiographic variables, as well as the symptomatic state after surgery. Follow-up was available in all patients (mean 23 +/- 14 months). Subtotal endocardiectomy and cryotherapy were associated in patients presenting with spontaneous or inducible ventricular arrhythmias (VA). Hospital mortality rate was 19.3%. Ejection fraction improved from 17 +/- 3% to 37 +/- 10% (p < 0.001); ventricular arrhythmias decreased significantly after surgery. Factors influencing early mortality at multivariate analysis were the presence of critical lesions on the circumflex artery and the duration of cardiopulmonary bypass. At 1-year control, a significant reduction in NYHA class was observed and no patient was in NYHA class IV. The improvement in ejection fraction was maintained (39 +/- 11%), as well as the reduction in inducible and spontaneous ventricular arrhythmias. There were 5 late deaths at follow-up, accounting for a late mortality of 10% at 5 years.