Value of the electrocardiogram in localizing the occlusion site in the left anterior descending coronary artery in acute anterior myocardial infarction

OBJECTIVES The study assessed the value of the electrocardiogram (ECG) as p redictor of the left anterior descending coronary artery (LAD) occlusion si te in relation to the first septal perforator (S1) and/or the first diagona l branch (D1) in patients with acute anterior myocardial infarction (AMI). BACKGROUND In anterior AMI, determination of the exact site of LAD occlusio n is important because the more proximal the occlusion the less favorable t he prognosis. METHODS One hundred patients with a first anterior AMI were included. The E CG showing the most pronounced ST-segment deviation before initiation of re perfusion therapy was evaluated and correlated with the exact LAD occlusion site as determined by coronary angiography. RESULTS ST-elevation in lead aVR (ST up arrow (aVR)), complete right bundle branch block, ST-depression in lead V5 (ST down arrow (V5) )and ST up arro w (V1) > 2.5 mm strongly predicted LAD occlusion proximal to S1, whereas ab normal Q-waves in V4-6 were associated with occlusion distal to S1 (p = 0.0 00, p = 0.004, p = 0.009, p = 0.011 and p = 0.031 to 0.005, respectively). Abnormal Q-wave in lead aVL was associated with occlusion proximal to D1, w hereas ST down arrow (aVL) was suggestive of occlusion distal to D1 (p = 0. 002 and p = 0.022, respectively). For both the S1 and D1, inferior ST down arrow greater than or equal to 1.0 mm strongly predicted proximal LAD occlu sion, whereas absence of inferior ST down arrow predicted distal occlusion (p less than or equal to 0.002 and p less than or equal to 0.020, respectiv ely). CONCLUSIONS In anterior AMI, the ECG is useful to predict the LAD occlusion site in relation to its major side branches. (C) 1999 by the American Coll ege of Cardiology.