Aspirin in a dose of 160 to 325 mg should be administered on day 1 of an acute MI and continued indefinitely on a daily basis. Thrombolytic therapy should be administered within 6 to 12 hours after the onset of an acute MI with ST segment elevation or with left bundle branch block. Primary coronary angioplasty when available should be used rather than thrombolytic therapy in the treatment of older persons with acute MI who are poor candidates for thrombolytic therapy. Intravenous heparin should be given in persons with acute MI undergoing primary coronary angioplasty or surgical coronary revascularization and in persons with acute MI at high risk for systemic embolization. Long-term oral warfarin should be given after MI for the secondary prevention of MI in post-MI persons unable to tolerate daily aspirin, in post-MI persons with persistent atrial fibrillation, and in post-MI persons with left ventricular thrombus. Platelet GP IIb/IIIa inhibitors should be administered along with aspirin and enoxaparin in the acute phase of management of persons with unstable angina pectoris or non-Q wave MI. Aspirin should be administered daily indefinitely to persons after MI, to persons with unstable angina pectoris, to persons with stable angina pectoris, and to persons undergoing coronary revascularization. Aspirin plus ticlopidine or aspirin plus clopidogrel should be used in persons undergoing coronary artery stenting. Platelet GP IIb/IIIa inhibitors should be used at the time of coronary angioplasty, coronary atherectomy, or coronary stenting. Aspirin, 160 to 325 mg daily, is recommended in older men and postmenopausal women who are at high risk for developing coronary events in addition to treating their coronary risk factors.