Factors predicting mortality in patients after myocardial infarction caused by left main coronary artery occlusion - Significance of ST segment elevation in both aVR and aVL leads

Acute left main coronary artery obstruction is rare and most patients in th is clinical setting die of sudden death or cardiogenic shock. During the pa st 8 years, we encountered 13 patients with acute myocardial infarction cau sed by total occlusion of the left main coronary artery (LMCA-AMI). Thus, w e surveyed these patients, and attempted to elucidate helpful predictors re lated to the prognosis. Six of 13 patients with LMCA-AMI survived. Successf ul left coronary artery dilatation was achieved in all survivors (group S), and in 5 (71%) non-survivors (group non-S). The age was not different betw een the two groups. A past history of angina was confirmed in 83% of group S, while only in 29% of group non-S. Clinical findings such as time of onse t of AMI, interval from the AMI onset to admission, elapsed period from the AMI onset to recanalization of LMCA and the value of CK on admission were not different between the two groups. However, cardiogenic shock occurred i n only 1 patient (17%) in group S compared with 5 patients (71%) in group n on-S. As emphasized in the literature, good collateral circulation to the l eft anterior descending artery was observed in 5 patients (83%) in group S, while not observed in group non-S. Electro cardiographically, ST elevation in the aVR lead was very characteristic. This finding was confirmed in 69% of the total patients. Noticeably, 5 out of 6 non-survivors (83%) showed S T elevation not only in leads a VR but also in the aVL lead. In addition to the absence of collateral circulation, this electrocardiographic findings, which obviously indicates the presence of extensive myocardial ischemia in the diseased heart, is a simple and important predictor suggesting a poor prognosis in LMCA-AMI patients.