We studied 70 cases of transmural myocardial infarction with first attack to look into the coronary anatomy of the infarct-related artery in the time course of infarction and evaluate the left ventricular wall motion according to patency of the infarct-related artery. The following result were obtained. 1) Among 70 cases with transmural myocardial infarction, 47(67.1%) had anterior infarction and 23 (32.9%) inferior infarction. Mean age of the total cases was 52.1+/-10.6 and M:F ratio was 7.8:1. 2) 28 cases were single vessel disease(40.0%), 19 cases were two vessel disease(27.1%), 18 cases werew three vessel disease(25.8%) and 5 cases had insignificant coronary stenosis (7.3%) with 4 cases of normal coronary artery. 3) The total occlusion rate of the infarct-related artery in 70 cases was 48.6%. The total occlusion rate of the 8 cases catheterized within 1 day was 87.5%, that of the 17 cases from 2nd to 15th day 52.9% that of the 23 cases from 16th day to 2nd month 39.1%, that of the 15 cases from 3rd to 12th month 40.0% and that 7 cases from 2nd and 6th year 42.8%. These results suggest that the natural resolution of the infarct-related artery has almost happened within 2 weeks. 4) The left ventricular ejection fraction was higher and the left ventricular end-diastolic pressure was lower in the group with incomplete occulsion of infarct-related artery than in those with complete occulsion, and left ventricular wall motion was better in the group with incomplete occulsion of the infarct-related artery than in those with complete occulsion.