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 predictor of the left anterior descending coronary artery (LAD) occlusion site in relation to the first septal perforator (S1) and/or the first diagonal branch (D1) in patients with acute anterior myocardial infarction (AMI). BACKGROUND In anterior AMI, determination of the exact site of LAD occlusion is important because the more proximal the occlusion the less favorable the prognosis. METHODS One hundred patients with first anterior AMI were included. The ECG showing the most pronounced ST-segment deviation before initiation of reperfusion therapy was evaluated and correlated with the exact LAD occlusion site as determined by coronary angiography. RESULTS ST-elevation in lead aVR (ST↑aVR), complete right bundle branch block, ST-depression in lead V5 (ST↓V5) and ST↑V1 >2.5 mm strongly predicted LAD occlusion proximal to S1, whereas abnormal Q-waves in V4–6 were associated with occlusion distal to S1 (p = 0.000, 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, whereas ST↓aVL was suggestive of occlusion distal to D1 (p = 0.002 and p = 0.022, respectively). For both the S1 and D1, inferior ST↓ ≥1.0 mm strongly predicted proximal LAD occlusion, whereas absence of inferior ST↓ predicted distal occlusion (p ≤ 0.002 and p ≤ 0.020, respectively). CONCLUSIONS In anterior AMI, the ECG is useful to predict the LAD occlusion site in relation to its major side branches.