Prognostic significance of ST segment depression in lateral leads I, aVL, V-5 and V-6 on the admission electrocardiogram in patients with a first acute myocardial infarction without ST segment elevation

OBJECTIVES We sought to investigate the short-term prognostic value of the admission electrocardiogram (ECG) in patients with a first acute myocardial infarction (MI)without ST segment elevation. BACKGROUND ST segment depression on hospital admission predicts a worse out come in patients with a first acute MI, but the prognostic information prov ided by the location of ST segment depression remains unclear. METHODS In 432 patients with a first acute MI without Qwaves or greater tha n or equal to 0.1 mV of ST segment elevation, we evaluated the ability of t he initial ECG to predict in-hospital death. RESULTS The presence, magnitude and extent of ST segment depression were as sociated with an increased mortality, but the only electrocardiographic var iable that was significant in predicting death after adjusting for baseline predictors was ST segment depression in two or more lateral (I, aVL, V-5-, or V-6) leads (odds ratio 3.5, 95% confidence interval 1.2 to 10.6). Patie nts with lateral ST segment depression (n = 91, 21%) had higher rates of de ath (14.3% vs. 2.6%, p < 0.001), severe heart failure (14.3% vs. 4.1%, p < 0.001) and angina with electrocardiographic changes (20.0% vs. 11.6%, p = 0 .04) than did the remaining patients, even though they had similar peak cre atine kinase, MB fraction levels (129 +/- 96 vs. 122 +/- 92 IU/liter, p = N S). In contrast, ST segment depression not involving the lateral leads did nor predict a poor outcome. Among patients who were catheterized, those wit h lateral ST segment depression had a lower left ventricular ejection fract ion (57 +/- 12% vs. 66 +/- 13%, p = 0.001) and more frequent left main coro nary artery or three-vessel disease than did the remaining patients (60% vs . 22%, p < 0.001). CONCLUSIONS In patients with a first non-ST segment elevation acute MI, ST segment depression in the lateral leads on hospital admission predicts a po or in-hospital outcome. (J Am Coll Cardiol 2000;35:1813-9) (C) 2000 by the American College of Cardiology.