Relation of ST-Segment changes in inferior leads during anterior wall acute myocardial infarction to length and occlusion site of the left anterior descending coronary artery

We investigated the relation between left anterior descending (LAD) coronar y artery morphology and inferior lead ST-segment changes to elucidate the c linical significance of such changes in 159 patients with anterior wall acu te myocardial infarction (AMI). Patients with I-vessel LAD artery lesions w ere divided into an ST depression group (n = 40), an ST elevation group (n = 25), and a no-ST-change group (n = 94) based on ST-segment changes in the inferior leads. The relation between each group and the infarct-related le sion and the presence of a wrapped LAD artery was then investigated. The pe rcentage of patients with the infarct-related lesion in the proximal LAD ar tery was significantly higher in the ST depression group and significantly lower in the ST elevation group. The percentage of patients with a wrapped LAD artery was significantly higher in the ST elevation group and significa ntly lower in the ST depression group. The wall motion index determined ech ocardiagraphically was significantly higher in the ST depression group and the no-ST-change group than in the ST elevation group. Our findings suggest that inferior lead ST-segment changes during anterior wall AMI arise as a result of competition between reciprocal changes caused by high lateral wal l AMI due to lesions of the proximal LAD artery, which depress the ST segme nt, and inferoapical wall AMI due to a wrapped LAD artery, which elevates t he ST segment. In patients with no ST-segment changes, echocardiography was useful for distinguishing the amount of affected LAD artery territory. (C) 2001 by Excerpta Medica, Inc.