Abstract: To study the significance of precordial ST segment depression in acute inferior myocardial infraction and its relation with lesion of coronary artery, 68 patients with inferior AMI were allocated into three groups based on the extent of precordial STsegment depression. Group 1(n=19) had no precordial ST segment depression. Group 2( n=14) had STsegment depression in V_1～3. Group 3(n=35) had STsegment depression in V_1～5 or V_1～6. Results: The frequency of disease of left anterior descending artery(LAD) was 26.3% in group 1, 14.3% in group 2, 74.3% in group 3. The patients with LAD stenosis of more than 90% accounted for 34.3% in group 3. The precordial STsegment depression in V_1～5 or V_1～6 in patients with inferior AMI suggest the presence of LAD lesion. The cause of ST segment depression in V_1～5 or V_1～6, may be due to anterior wall subendocardial ischemia caused by severe stenosis of LAD, and precordial ST segment depression in V_1～3 indicates a reciprocal change.

Key words: acute inferior myocardial infarction, precordial ST segment depression, lesion of coronary artery