Identification of the culprit artery involved in inferior wall acute myocardial infarction using electrocardiographic criteria.

We tested whether particular electrocardiogram (ECG) changes can identify the right coronary (RCA) or left circumflex (LCX) artery as the responsible vessel in inferior wall acute myocardial infarction (AMI) in 73 patients. A standard 12-lead ECG was performed within 6 h of onset of chest pain. Coronary angiography was performed between 1 week and 6 weeks after the infarction. RCA and LCX lesions were detected in 53 and 20 patients, respectively. The most useful ECG parameters for implicating the RCA were a higher ST elevation in lead III than lead II (specificity 94%, sensitivity 86%) and an S/R wave ratio > 0.33 plus ST segment depression > 1 mm in lead aVL (specificity 94%, sensitivity 92%). Absence of these criteria was associated with LCX occlusion (specificity 100%, sensitivity 87%). These results indicate that composite ECG criteria are useful in predicting the artery involved in inferior wall AMI.