Demographic and Prognostic Profiles of Infarct-Related Arteries in Acute Inferior Myocardial Infarction
Abstract
Background: Inferior myocardial infarction (IMI) constitutes a significant subset of acute coronary syndromes, with coronary artery involvement playing a crucial role in prognosis and therapeutic strategies. Objective: The objective were to determine the prevalence and patterns of arterial involvement, to assess demographic and clinical features, and to evaluate the implications for clinical practice. Methodology: This retrospective cohort study was performed at a Dhaka tertiary cardiology center in Bangladesh where reviewed 600 consecutive acute IMI cases (ST-elevation ≥1 mm in ≥2 inferior leads II/III/aVF plus biomarkers) admitted January to December 2024, excluding CABG priors, non-inferior MI, incomplete angiography, or late transfers from 1,248 screened. Emergent CAG within 24 hours captured demographics, risks, ECG/angiographic details (IRA, dominance, TIMI/SYNTAX), and outcomes via EHR/syngo extraction by blinded dual-reviewers, with less than 3.0% missing data imputed. Results: In 600 patients with inferior myocardial infarction (IMI), the mean age was 62.4 ± 11.3 years, with males predominant at 68.0% and key risk factors including hypertension (58.0%), diabetes (34.0%), and smoking (41.0%). Coronary angiography revealed the right coronary artery (RCA) as the infarct-related artery in 72.0%, left circumflex (LCx) in 24.0%, and dual/ambiguous in 4.0%, with right dominance overall at 82.0% and significantly linked to RCA cases (85.0%, p<0.01). RCA involvement associated with male sex (71.0% vs. 63.0%, p=0.03), younger age (60.8 vs. 66.1 years, p<0.01), and higher complete heart block (18.0% vs. 9.0%, p=0.02), while LCx cases showed more heart failure (14.0% vs. 8.0%, p=0.04). Multivariable analysis identified right dominance as the strongest RCA predictor (OR 2.7, 95% CI 1.8-4.2), with equivalent in-hospital mortality (5.2% vs. 4.8%, p=0.81). Conclusion: This study confirms RCA as the predominant culprit in most cases of IMI cases with strong right dominance association, highlighting distinct clinical profiles bradycardic complications in RCA versus heart failure in LCx while equivalent low mortality underscores timely PCI efficacy, advocating pre-CAG ECG/dominance assessment for optimized management. Journal of National Institute of Neurosciences Bangladesh, July 2025;11(2):144-149