Follow-up catheterization of patients with myocardial infarction during coronary artery bypass surgery.

Of 197 consecutive patients having aortocoronary bypass grafts over a 30 month period, 38 (19 per cent) had ECG evidence of myocardial infarction. The infarctions occurred more commonly in patients receiving multiple grafts. The infarctions were usually in areas supplied by grafted vessels. The infarctions occurred most often in the inferior wall, even when multiple vessels were grafted. Eleven patients with intraoperative infarction have had repeat postoperative coronary arteriograms. Seven had all grafts patent; three of these patients had hypokinesis of the infarcted wall. Four of the 11 patients had one or more occluded grafts; three of these patients had an area of hypokinesis. We conclude that intraoperative myocardial infarction is a common problem in aortocoronary bypass surgery and is not necessarily caused by graft occlusion.