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Abstract

Objectives: This study aims to identify specific electrocardiographic (ECG) indicators of left circumflex artery (LCX) occlusion in acute inferior myocardial infarction (MI), thereby improving diagnostic accuracy.
Methodology: This prospective study was conducted at Mansoura University Hospital on 50 patients with angiographically confirmed acute inferior MI. Patients with ST-segment elevation in inferior leads and LCX as the infarct-related artery were included. Demographic data, clinical characteristics, and ECG findings were documented, and ST-segment elevation patterns were analyzed to evaluate their sensitivity and specificity in predicting LCX involvement.
Results: Among the 50 patients, 67.5% of those with LCX occlusion exhibited greater ST-segment elevation in lead II compared to lead III, whereas this pattern was observed in only 30% of patients with right coronary artery (RCA) occlusion (p = 0.03). This criterion demonstrated a sensitivity of 84.85% and specificity of 93.94% for detecting LCX occlusion. Additionally, ST-segment depression in lead aVR was present in 32.5% of LCX cases versus 70% in RCA cases. The mean age was 56.84 ± 9.71 years for the LCX group and 54.67 ± 12.4 years for the RCA group, with comparable rates of comorbidities. No significant differences were observed in mortality rates (7.5% LCX vs. 10% RCA) or major cardiac events (20% in both groups).
Conclusion: ST-segment elevation in lead II exceeding that in lead III serves as a reliable ECG indicator for identifying LCX as the culprit artery in acute inferior MI. This finding provides a valuable tool for prompt and accurate diagnosis.