Impact of right ventricular involvement on mortality and morbidity in patients with inferior myocardial infarction

OBJECTIVES We sought to evaluate the prognostic impact of right ventricular (RV) myocardial involvement in patients with inferior myocardial infarctio n (MI). BACKGROUND There is uncertainty regarding the risk of major complications i n patients with inferior MI complicated by RV myocardial involvement. Wheth er these complications are related to RV myocardial involvement itself or s imply to the extent of infarction involving the left ventricle (LV) is also unknown. METHODS We examined the incidence of death and mechanical and electrical co mplications in patients with (n = 491) and without (n = 638) RV myocardial involvement and in patients with anterior MI (n = 971) in an analysis from the Collaborative Organization for RheothRw Evaluation (CORE) trial. Left v entricular infarct size was assessed by technetium-99m-sestamibi single-pho ton emission computed tomography and peak creatine kinase, and LV function was assessed by radionuclide angiography. We also performed a meta-analysis in which we pooled the results of our study with previous smaller studies addressing the same question. RESULTS Six-month mortality was 7.8% in inferior MI compared with 13.2% in anterior MI. Among patients with inferior MI, serious arrhythmias were sign ificantly more common in patients with RV myocardial involvement who also h ad a trend toward higher mortality, pump failure and mechanical complicatio ns. However, this was not associated with a difference in LV infarct size o r function. A meta-analysis of six studies (n = 1,198) confirmed that RV my ocardial involvement was associated with an increased risk of death (odds r atio [OR] 3.2, 95% confidence interval [CI] 2.4 to 4.1), shock (OR 3.2, 95% CI 2.4 to 3.5), ventricular tachycardia or fibrillation (OR 2.7, 95% CI 2. 1 to 3.5) and atrioventricular block (OR 3.4, 95% CI 2.7 to 4.2). CONCLUSIONS Patients with inferior MI who also have RV myocardial involveme nt are at increased risk of death, shock and arrhythmias. This increased ri sk is related to the presence of RV myocardial involvement itself rather th an the extent of LV myocardial damage. (J Am Coil Cardiol 2001;37:37-43) (C ) 2001 by the American College of Cardiology.