Five hundred and fourteen cases with acute myocardial infarction were admitted to our hospital during the past 5 years, since April 1990. Among 343 cases who had emergency coronary angiography, 53 cases had coronary artery bypass grafting surgery within 2 weeks after the onset of acute myocardial infarction. Mean number of bypass grafts was 2.9 +/- 0.9/patient, and operative mortality was 25% (13/53). Clinical condition immediately before the surgery and surgical mortality was, shock state in 20 cases (mortality 50%), IABP dependent state in 23 cases (mortality 13%), post-infarction angina in 8 cases (mortality 0%). Mortality in 8 cases whose infarct-related artery was left main trunk was as high as 63%. Eight of 9 cases whose cardiac indices were below 2.01/min/m2 immediately after the surgery died of pump failure. On the contrary, only 2 of 37 cases whose post-operative cardiac indices were above 2.01/min/m2 died of non-cardiac reason. To improve the surgical results, we concluded that powerful mechanical support such as ventricular assist system should be applied to post-operative pump failure cases whose cardiac indices were below this limit despite the aid of IABP.