Clinical Implication of ST Segment Depression in aVR & aVL in Patients with Acute Inferior Wall Myocardial Infarction

Objectives: The aim of the study was to assess the role of ST segment depression in the limb leads aVR and aVL for the diagnosis of acute posterior wall infarction and the identification of infarct related artery (IRA) in patients with acute inferior wall MI. Methods: In 159 patients with I-STEMI, 127 (80%) had RCA occlusion and 32 (20%) had LCX occlusion. In the ECG algorithms, RCA occlusion was indicated by ST depression in lead aVL higher than lead aVR and no ST depression in lead aVL and aVR. LCX occlusion was indicated by ST depression in lead aVR higher than or equal to lead aVL and no ST depression in aVL and aVR. Results: The sensitivity, specificity, positive and negative predictive values of these algorithms were high (98%, 82%, 92% and 95% for RCA occlusion and 83%, 98%, 95% and 92% for LCX occlusion). Conclusion: The ECG algorithms can reliably identify the culprit artery in I-STEMI. ST segment depression in limb leads aVR and aVL with avR ≥ aVL helps to diagnose left circumflex artery as a culprit IRA in an acute inferior wall MI.