Localising culprit artery in inferior STEMI

Background: ST elevation myocardial infarction (STEMI) represents a cardiac emergency. Time to diagnosis, identification of culprit lesion, and intervention are important. Inferior STEMI represents a dilemma for cardiologists. The territory can be supplied by the right coronary artery (RCA) or the left circumflex coronary artery (LCx). Diagnostic algorithms have been proposed to predict the culprit artery.

Methods: We performed a single-centre retrospective cohort analysis of all patients admitted to our hospital from 2008 to 2020 with a diagnosis of inferior STEMI. We examined the diagnostic 12 lead ECG for quantification of ST elevation in leads II and III and compared this to culprit lesion found on angiography.

Results: There were 304 patients identified with STEMI in our database; 105 were found to have an inferior myocardial infarction by ECG criteria. Ninety-nine were included in our study with either RCA or LCx culprit lesions on angiography (82 males, 17 females). The average age of these patients was 64.9 years old. Sensitivity, specificity, positive predictive value and negative predictive value for ST elevation in lead II exceeding lead III predicting LCx culprit lesion was 0.32 (95% CI 0.13 to 0.57), 0.94 (95% CI 0.86 to 0.98), 0.55 (95% CI 0.29 to 0.78), 0.85 (95% CI 0.81 to 0.89), respectively. Sensitivity, specificity, positive predictive value and negative predictive value for ST elevation in lead III exceeding lead II predicting RCA culprit lesion was 0.94 (95% CI 0.86 to 0.98), 0.32 (95% CI 0.13 to 0.57), 0.85 (95% CI 0.81 to 0.89), 0.55 (95% CI 0.29 to 0.78), respectively.

Conclusions: In inferior STEMI, comparison of ST elevation in leads II and III can reliably predict culprit lesion artery and guide intervention.

Subject indexing: Culprit artery localisation, inferior stemi, ECG.