Advances in cardiovascular pharmacology and monitoring, cardiac catheterization, and cardiovascular surgical techniques have made emergency coronary artery bypass surgery relatively safe for acute myocardial ischemia and infarction. The results are starting to approach those in the nonacute situation and are improving survival over previous nonsurgical management. Further advances in limiting myocardial infarction size and reperfusion injury will enhance the safety of emergency coronary artery surgery and increase the amount of myocardium that can be returned to a functional state. At present, left ventricular dysfunction, especially when severe enough to result in cardiogenic shock, is the major incremental risk factor for postinfarction surgery. The interval between infarction and surgery in itself does not seem to have a strong effect on operative risk. If operation can be performed within 8 hours of infarction, risk is low and myocardial salvage is probable. After 8 hours, surgery seems advisable if residual critical lesions or active myocardial ischemia is present, regardless of ejection fraction or postinfarction interval.