This study reports hemodynamic, electrophysiologic, and clinical results in 171 patients (157 men and 14 women, mean age 57 +/- 8 years) 1 year after endoventricular circular patch repair and coronary grafting for postinfarction left ventricular dyskinetic or akinetic aneurysm. All patients had hemodynamic and electrophysiologic study before the operation and early and 1 year after the operation. The vast majority of aneurysms were anterior (n = 166), with a mean delay from infarction of 43 +/- 50 months. Fifty-two percent of patients were in New York Heart Association class III or IV, and preoperative ejection fraction was less than 40% in the majority of them (75%). Preoperative clinical ventricular tachycardia was present in 25 patients and was inducible in 59 patients. All patients had endoventricular circular patch repair with a synthetic (n = 99) or autologous patch (n = 72); 96% had associated coronary grafting with a mean number of bypass grafts of 1.9 +/- 0.9. Results at 1 year demonstrated a significant increase in ejection fraction (from 36% +/- 13% to 46% +/- 12% (p < 0.0001) and a significant reduction in ventricular volumes (end-diastolic volume index from 116 +/- 5 to 94 +/- 29 ml/m2 and end-systolic volume index from 77 +/- 45 to 53 +/- 25 ml/m2, p < 0.0001). New York Heart Association functional classification was significantly improved (2.6 +/- 0.9 vs 1.4 +/- 0.6, p < 0.0001) and ventricular tachycardias were almost suppressed (no documented clinical ventricular tachycardias and 8% incidence of inducible ventricular tachycardias after 1 year, chi 2 < 0.001). Patients who benefit most from the operation are those with more severe preoperative left ventricular dysfunction (i.e., ejection fraction < 30%), more frequent ventricular arrhythmias, and larger ventricular volumes. At regression analysis, critical disease of the right coronary artery was the only independent predictor of unsatisfactory pump improvement (as evaluated by postoperative increase of ejection fraction < 10 absolute points). In conclusion, in our large series of patients operated on by one surgical team between 1988 and 1993, who were studied hemodynamically both before and after the operation, endoventricular circular patch repair of left ventricular aneurysm associated with coronary grafting definitely improves left ventricular pump function and clinical status 1 year after the operation.