Isolated Left Circumflex Coronary Artery Occlusion as a Cause of Myocardial Infarction

Abstract

The relation of electrocardiographic (ECG) patterns to clinical spectrum and angiographic features was assessed in 47 patients with a first myocardial infarction due to isolated left circumflex coronary artery (LCX) occlusion and compared to that in 51 patients with right coronary artery (RCA)-related infarction. The occurrence of inferior Q waves and an abnormal R wave in lead V(1) were more frequent in patients with LCX-related infarction (46 vs. 7% and 51 vs. 4%, respectively). Compared to patients with LCX-related infarction without an abnormal R wave in lead Vi and those with RCA occlusion, patients with LCX-related infarction and an abnormal R wave in lead V) associated with inferior and/or lateral Q waves had larger left ventricular enddiastolic and end-systolic volumes, a lower ejection fraction, a higher incidence of total occlusion of a dominant LCX without collaterals and more cardiac events during follow-up. The study suggests that (1) the presence of lateral Q waves and an abnormal R wave in lead V i after myocardial infarction may be a useful marker of LCX occlusion and (2) patients with LCX-related infarction may have a different status of left ventricular function depending on the size of circulation and the status of residual flow to the infarct region during LCX occlusion.