Beyond the inferior wall: long-term consequences of right ventricular involvement in acute myocardial infarction

Background Inferior myocardial infarction (MI) with right ventricular (RV) involvement is a frequently associated with conduction abnormalities, hemodynamic compromise, and adverse outcomes. While acute-phase characteristics are well described, data on 1-year prognosis (including predictors of RV systolic recovery) remain limited. This study aimed to evaluate outcomes in patients with inferior MI and RV extension, focusing on culprit artery distribution, conduction disturbances, and RV functional recovery measured by tricuspid annular plane systolic excursion (TAPSE) and tissue Doppler S′. Methods In this retrospective, single-centre study, we analysed 391 consecutive patients admitted to a tertiary cardiac intensive care unit (CICU) for inferior ST-elevation MI between January 2015 and December 2024 at a tertiary cardiac centre. RV involvement, defined by right precordial ST elevation ≥1 mm and/or echocardiographic evidence of RV dysfunction, was present in 127 patients (32%). All patients underwent coronary angiography and guideline-directed therapy. The primary endpoint was 1-year all-cause mortality. Secondary endpoints included heart failure (HF) hospitalization, ventricular arrhythmias, complete atrioventricular (AV) block, permanent pacemaker (PM) implantation, and RV systolic function. Multivariate analysis identified predictors of incomplete RV recovery at 12 months. Results The right coronary artery (RCA) was the culprit in 86% of patients with RV involvement versus 68% in those without (p<0.001). Cardiogenic shock developed in 18% of patients with RV involvement compared with 6% without (p<0.001), frequently associated with extensive RCA occlusion and severe RV dysfunction. Complete AV block occurred in 31% of RV cases versus 9% without (p<0.001);14% required permanent PM implantation (p=0.01)(figure 1). At 1 year, mortality was higher in the RV involvement group (14% vs. 6%,p=0.01), with RV involvement independently predicting death (HR 1.7, 95% CI 1.1–2.8,p=0.02). HF hospitalization and sustained ventricular arrhythmias were also more frequent in RV cases (12% vs. 5%,p<0.001; 8% vs. 3%,p=0.02). Echocardiographic follow-up at 12 months (available in 85% of survivors) demonstrated significant RV systolic recovery: TAPSE improved from 13.6±2.8 mm to 18.2±3.1 mm (p<0.001), and S′ from 8.0±1.8 cm/s to 10.5±1.7 cm/s (p<0.001). Independent predictors of incomplete RV recovery included baseline TAPSE<12mm, baseline S′<7 cm/s, delayed (>12h) or incomplete revascularization (TIMI flow<3), presence of multivessel disease, and reduced left ventricular ejection fraction (<40%) at discharge (p<0.05)(figure 2). Conclusions Inferior MI with RV extension is associated with higher 1-year mortality, HF hospitalization, arrhythmias, and AV block requiring pacing. Baseline RV dysfunction, incomplete reperfusion, multivessel disease, and reduced LV function are key predictors of RV non-recovery, emphasizing the importance of early intervention.