ECG discrimination between right and left circumflex coronary arterial occlusion in patients with acute inferior myocardial infarction: value of old criteria and use of lead aVR.
OBJECTIVE
Prior studies have proposed several ECG criteria for identifying the culprit artery in patients with acute inferior myocardial infarction (MI). We applied each criterion to our patients to assess its utility. In doing so, we discovered a previously unreported, but highly useful, criterion utilizing lead aVR.


METHODS
Retrospective review.


METHODS
Thirty consecutive patients with symptoms of acute MI, ST-segment elevation in the inferior ECG leads, an appropriate rise and fall of creatine kinase and troponin I levels, and coronary arteriography within 7 days of the onset of symptoms.


METHODS
The ECG recorded within 24 h of the onset of symptoms that had the most prominent ST-segment changes was analyzed. In the 12 standard leads and in lead V(4)R, ST-segment elevation or depression was measured 0.06 s after the J point.


RESULTS
Four previously described criteria were useful in identifying the right coronary artery (RCA) or the left circumflex coronary artery (LCX) as the culprit: ST-segment elevation in lead I, ST-segment more or less elevated in lead II than in lead III, ST-segment elevation >or= 0.5 mm in lead V(4)R, and various combinations of ST-segment elevation or depression in leads V(1) and V(2). A new criterion was found to be at least as useful as any previously described: the presence and amount of ST-segment depression in lead aVR.


CONCLUSIONS
At least five different ST-segment criteria help to identify the RCA or the LCX as the culprit artery in patients with acute inferior MI. One of these, the amount of ST-segment depression in lead aVR, has not been reported previously and needs validation in a larger study.
Section of Cardiology, Department of Medicine, Louisiana State University Health Sciences Center and the Medical Center of Louisiana, New Orleans, LA 70112, USA.
Radhakrishnan
R
Nair
D Luke
DL
Glancy
D017023:Coronary Angiography; D003327:Coronary Disease / Q000175:diagnosis*; D003331:Coronary Vessels / Q000473:pathology*; D004562:Electrocardiography; D006801:Humans; D009203:Myocardial Infarction / Q000209:etiology*; D012189:Retrospective Studies; D012680:Sensitivity and Specificity