[摘要]：During inferior acute myocardial infarction, ST-segment elevation (ST up arrow) often occurs in leads V-5 to V-6, but its clinical implications remain unclear. We examined the admission electrocardiograms from 357 patients with a first inferior acute myocardial infarction who had Thrombolysis In Myocardial Infarction 3 flow of the right coronary artery or left circumflex artery within 6 hours after symptom onset. The patients were divided according to the presence (n = 76) or absence (n = 281) of ST up arrow >2 mm in leads V-5 and V-6. Patients with ST up arrow in leads V-5 and V-6 were subdivided into 2 groups according to the degree of ST up arrow in leads III and V-6: ST up arrow in lead III greater than in V-6 (n = 53) and ST up arrow in lead III equal to or less than in V-6 (n = 23). The perfusion territory of the culprit artery was assessed using the angiographic distribution score, and a mega-artery was defined as a score of ST up arrow in leads V-5 and V-6 with ST up arrow in lead III greater than in V-6 and ST up arrow in leads V-5 and V-6 with ST up arrow is in lead III equal to or less than in V-6 were associated with mega-artery occlusion and impaired myocardial reperfusion, as defined by myocardial blush grade 0 to 1. Right coronary artery occlusion was most common (96%) in the former, and left circumflex artery occlusion was most common (96%) in the latter, especially proximal left circumflex occlusion (74%). Multivariate analysis showed that ST up arrow in leads V-5 and V-6 with ST up arrow in lead III greater than that in V-6 (odds ratio 4.81, p <0.001) and ST up arrow is in leads V-5 and V-6 with ST up arrow in lead III equal or less than that in V-6 (odds ratio 5.96, p <0.001) were independent predictors of impaired myocardial reperfusion. In conclusion, ST up arrow is in leads V-5 and V-6 suggests a greater risk area and impaired myocardial reperfusion in patients with inferior acute myocardial infarction. Furthermore, comparing the degree of ST up arrow in lead V-6 with that in lead III is useful for predicting the culprit artery. (C) 2012 Elsevier Inc. All rights reserved. (Am J Cardiol 2012;109:314-319)
