Fourteen consecutive patients undergoing left ventricular aneurysmectomy and coronary artery bypass grafting were studied by multiple gated ventricular scintigraphy at rest and during exercise before and at six weeks and six months after surgery. All had congestive heart failure and 12 angina pectoris. Before operation left ventricular ejection fraction fell significantly with exercise, as did the regional wall motion score. Six weeks after surgery all surviving patients were free of angina, with an improvement in functional class; the total exercise workload improved significantly, but resting left ventricular ejection fraction was unchanged; the regional wall motion score improved in both the anterior and left anterior oblique projections, although extensive areas of abnormal contraction persisted. Exercise left ventricular ejection fraction improved significantly after operation at six weeks, and previous exercise induced abnormalities of regional contraction were abolished. Six months after operation angina pectoris had recurred in one patient, but there was no further change in ventricular function in the remainder. Although resting ejection fraction is not improved, symptoms, exercise workload, and exercise ventricular function can be improved by aneurysmectomy and coronary artery bypass grafting, but the respective contribution of these two procedures remains uncertain.