Left ventricular (LV) aneurysms were resected in 27 patients for treatment of congestive heart failure and in five patients for treatment of ventricular arrhythmia. There were eight early (25 per cent) and five late (15 per cent) deaths. Preoperative hemodynamics including analysis of left ventriculograms in the right anterior oblique position did not consistently predict survival. In contrast, coronary artery anatomy appeared to influence the mortality rate strikingly in patients with congestive heart failure. The hospital mortality rate was 6 per cent and the late mortality rate was 13 per cent for 16 patients with one-or two-vessel coronary artery disease, but with unobstructed LV lateral wall blood supply. All but one of the survivors obtained a good late result. In nine patients with two-and three-vessel coronary artery disease and obstructed LV lateral wall blood supply there were six hospital deaths and two late deaths. It is concluded that the presence or absence of occlusive disease in the arteries supplying the LV lateral wall is an important determinant of the mortality rate associated with resection of anterior apical LV aneurysms in patients with severe congestive heart failure.