A simple electrocardiographic finding can be a powerful guide in identifying the culprit artery during inferior myocardial infarction. A study published in the Journal of Electrocardiology evaluated 43 previously reported ECG criteria in 431 patients who underwent primary percutaneous coronary intervention at Gia Dinh Hospital between January 2019 and August 2024.

The cohort had a mean age of 62.1 ± 12.2 years, and 76.1% were men. Among them, 14.6% had single-vessel, 31.6% had double-vessel, and 53.8% had triple-vessel coronary disease. The ST elevation (STE) in lead III greater than in lead II emerged as the best predictor of right coronary artery (RCA) occlusion, with 92% sensitivity, 67% specificity, 94% positive predictive value, and 88% overall accuracy (AUC = 0.8; 95% CI 0.74–0.85; p < 0.001).

Importantly, this single ECG criterion retained its diagnostic strength in patients with multivessel disease, maintaining a sensitivity of 92% and a predictive value of 95%. The findings confirm that the STE III > II sign remains a quick, dependable, and clinically useful marker for identifying the culprit vessel in inferior MI, supporting faster decision-making in acute cardiac care.