BACKGROUND: The lead aVR is the mostly ignored lead while interpreting a 12-lead ECG but it was found out to be very valuable in the field of clinical electrocardiography. It can be very helpful in ischemia heart disease in diagnosing the site of coronary artery occlusion and size of the area at risk. The purpose of this study is to determine if ST segment elevation in lead aVR can predict critical left main coronary artery (LMCA) stenosis in acute coronary syndrome. And to determine if the ST segment depression in precordial lateral leads (V5 to V6) is an added criterion for LMCA lesion during acute chest pain.
MATERIALS AND METHODS: This is a retrospective, cross sectional study. The correlation between ST segment elevation in lead aVR, ST segment depression in V4 to V6 and infarct related artery (IRA) was examined in 554 patients with acute coronary syndrome. The IRA was defined as the most severe and/or that the lesion with thrombus by coronary angiography.
RESULTS: A total of 554 patients were included in this study. Among this patients, IRA was left main coronary artery (LMCA) in 82 patients, left anterior descending artery (LAD) in 256 patients, left circumflex artery (LCx) in 30 patients, right coronary artery (RCA) in 111 patients and those with three-vessel disease (3VD) in 75 patients. The ST segment elevation in lead aVR was present in 134 patients (24 percent) among 554 patients. The ST segment elevation in lead aVR was present in 90.2 percent (74/82) of LMCA, 34.7 percent (26/75) of 3VD, 10.5 percent (27/256) of LAD, 6.32 percent (7/111) of RCA and none from the LCx (p<0.000). The ST segment elevation in lead aVR was specific for LMCA lesion (sensitivity; 90.2 percent, specificity; 87.3 percent, positive predictive value; 55.2 percent, negative predictive value; 98.1 percent). The ST segment depression in leads V4 to V6 was also present in 150 patients (27 percent) among 554 patients. The ST segment depression in leads V4 to V6 was present in 94 percent (77/82) of LMCA, 73 percent (55/75) of 3VD, 3.7 percent (11/30) of LCx, 1.9 percent (5/256) of LAD and 1.8 percent (2/111) of RCA (p<0.000). The ST segment depression in leads V4 to V6 was specific for LMCA lesion (sensitivity; 93.9 percent, specificity; 98.1 percent, positive predictive value; 93.9 percent, negative predictive value; 98.1 percent).
CONCLUSION: In acute coronary syndrome, ST segment elevation in lead aVR and ST segment depression in V4 to V6 are present in majority of patients with LMCA lesion and in minority of patients with proximal left descending artery lesion and with three-vessel disease. RECOMMENDATION: Early aggressive treatment should be done in these particular subsets of patient. Hence coronary angiography with revascularization are needed to save these high-risk patients.