Electrocardiographic localization of the occlusion site in left anterior descending coronary artery in acute anterior myocardial infarction.

BACKGROUND: The site of occlusion of left anterior descending coronary artery is important in acute anterior myocardial infarction because, proximal occlusion is associated with less favorable outcome and prognosis. The present study attempted to evaluate the electrocardiographic correlate of the location of the site of the left anterior descending coronary artery occlusion with respect to first septal perforator and/or the first diagonal branch.

METHODS AND RESULTS: The study included 50 patients with a first acute anterior myocardial infarction. The electrocardiogram with the most pronounced ST segment deviation before the start of reperfusion therapy was evaluated and correlated with the left anterior descending occlusion site as determined by coronary angiography. ST segment elevation in lead aVR, ST segment depression in lead V5 and ST segment elevation in V1>2.5 mm strongly predicted left anterior descending occlusion proximal to first septal, whereas abnormal Q wave in V4-6 was associated with occlusion distal to first septal. Abnormal Q wave in lead aVL was associated with occlusion proximal to first diagonal, whereas ST depression in lead aVL was suggestive of occlusion distal to first diagonal branch. For both first septal and first diagonal, ST segment depression > or =1 mm in inferior leads strongly predicted proximal left anterior descending artery occlusion, whereas absence of ST segment depression in inferior leads predicted occlusion distal to first septal and first diagonal. All the patients were followed during their in-hospital stay (median of 7 days), during which four patients in the proximal to first septal and first diagonal group and one patient in the distal to first septal and first diagonal group died (p < or = 0.001).

CONCLUSIONS: In acute myocardial infarction electrocardiogram is useful to predict the left anterior descending occlusion site in relation to its major side branches and such localization has prognostic significance.