SUMMARYLittle information is available relating the extent of coronary atherosclerosis and myocardial infarct size measured at autopsy to clinical information. We correlated data from 85 patients who died 1 day to 6 months after a myocardial infarction. Of 70 patients who had coronary artery analysis at the time of autopsy,67 had significant (greater than 70%) occlusion of one or more major coronary arteries. The number of vessels with significant occlusion was not greater in patients with a history of hypertension, diabetes or lipid abnormalities, but patients with these risk factors died at a younger age. The extent of atherosclerosis did not correlate with functional or clinical class, length of survival, or heart weight at autopsy. Almost all patients (84%) with a clinical history of two or more infarctions had two or more vessels with greater than 70% occlusion.Gross and microscopic myocardial infarct size was measured at autopsy. There was an inverse relation between the percentages of old and new infarct. Total infarct size was related to the number of vessels with significant occlusion in the four major coronary arteries. The total percentage of old infarct was increased in patients with a history of prior myocardial infarction. Left ventricular and septal rupture occurred in patients with a significantly greater amount of recent necrosis, whereas patients with left ventricular aneurysm had more old myocardial infarct with a smaller amount of new necrosis.We concluded that myocardial infarct size at autopsy is closely related to the number of vessels with greater than 70% occlusion. In addition, patients with a history of myocardial infarction or with left ventricular aneurysm have a greater extent of old infarct and total necrotic tissue than patients with only new infarcts, who more frequently die of left ventricular or septal rupture.