[Electrocardiographic discrimination of infarct-related artery between left circumflex and right coronary artery: comparison of ST elevation between leads II and III].

OBJECTIVES: Admission electrocardiography was evaluated to discriminate left circumflex artery (LCX) versus right coronary artery (RCA) as the cause of acute myocardial infarction.
METHODS: Electrocardiographic findings were assessed in patients with RCA (n = 60) and LCX (n = 60) occlusion.
RESULTS: ST segment elevation in the inferior leads or right precordial leads was more common in the RCA group. ST segment depression or negative T wave was more common in leads I, aVL in the RCA group. ST segment elevation was more common in leads V5, V6 in the LCX group. ST segment was elevated in inferior leads in 55 patients in the RCA group and 27 patients in the LCX group. Mean ST level was higher in lead III than in lead II in the RCA group, but not in the LCX group. The ST level was higher in lead III than in lead II in 78% of the RCA group, but only 44% of the LCX group (p < 0.01).
CONCLUSIONS: Comparison of ST levels between leads II and III, and a three-dimensional analysis in 12-lead electrocardiography is useful for discriminating the left circumflex artery from the right coronary artery as the cause of acute myocardial infarction.