It is our practice to suggest coronary arteriography for patients with impending myocardial infarction who respond poorly to medical managemnt. Aortocoronary saphenous vein bypass surgery is advised for patients with unstable angina and left main coronary disease. Surgery is not advised for patients with minimal irregularities of the coronary arteries (less than 50% obstruction). Rarely is surgery advised for patients with the syndrome of impending myocardial infarction in whom only the right coronary artery or the left circumflex artery is obstructed. Bypass surgery should be seriously considered for patients with unstable angina and hemodynamically significant disease involving the proximal left anterior descending coronary artery (proximal to the first septal perforating branch). On the basis of symptomatic improvement alone, surgically treated patients with the syndrome of impending myocardial infarction seem to fare better than do those treated medically.