Background & Objective: Electrocardiography is a useful method in predicting coronary artery occlusion site, left ventricular function and the prognosis of patients with acute myocardial infarction. Accurate localization of coronary artery occlusion and the extent of ischemic area are very important in decision making for invasive procedures to restore coronary perfusion.

  Methods: In this prospective study the abnormal findings of first recorded electrocardiogram in 100 patients with acute myocardial infarction w ere compared with coronary angiography findings and the value of ST-T changes in predicting coronary artery occlusion site was evaluated.

  Results: In acute anterior wall infarction, ST elevation in aVR (p=0.001), right bundle branch block (p=0.001) and ST depression in V5 strongly predicts LAD occlusion at its proximal part. Also ST depression, especially equal or more than 1 mm, in inferior leads indicates proximal LAD occlusion. The absence of such ST depression in these inferior leads correlates with distal LAD occlusion (p=0.01).ST depression of aVL also is a sign of distal LAD occlusion (p=0.01).In acute inferior wall infarction ≥ 1 mm ST depression in leads I, aVL and greater ST elevation in lead III than lead II refers to RCA involvement.

  Conclusion: In acute anterior myocardial infarction electrocardiography can help to differentiate proximal LAD lesion from its distal involvement. Also it is useful in determining the culprit vessel in acute inferior wall infarction and helps to recognize high risk patients with major benefit from invasive reperfusion strategies.