The value of ECG lead aVR in the differential diagnosis of acute inferior wall myocardial infarction.

OBJECTIVES: To investigate whether the ST changes in the aVR lead on 12-lead ECG can be used to identify infarct-related artery (IRA) in patients with acute inferior myocardial infarction.

METHODS: The ECG features were studied in 90 patients with acute inferior myocardial infarction where IRA was confirmed by coronary angiography.

RESULTS: Right coronary artery (RCA) and the left circumflex coronary artery (LCX) were identified as IRA in 70 and 20 patients, respectively. ST depression in aVR > or = 0.1 mV was found in 14 (70%) patients who had LCX as the IRA, and in 4 (5.7%, p<0.001) patients with RCA as IRA. Using ST segment depression > or = 0.1 mV in aVR as a criterion, the sensitivity and specificity in differentiating LCX as IRA was 70.0% and 94.3%, respectively.

CONCLUSIONS: ST depression in aVR is common in patients with LCX-related acute inferior myocardial infarction. The ST changes in this lead are associated with an excellent specificity and a good sensitivity in differentiating LCX from RCA as the IRA.