Predictors and Importance of Congestive Heart Failure in Patients with Acute Inferior Myocardial Infarction

Abstract

Inferior myocardial infarction (MI) is considered to have a more favorable prognosis than anterior wall MI but includes high risk groups with increased mortality and morbidity. It is well known that congestive heart failure (CHF) complicating acute MI has poor prognosis. In this study we assessed the clinical and prognostic significance of CHF and the predictive value of the baseline demographic and clinical variables for CHF in patients with acute inferior MI. A total of 350 patients with acute inferior MI were included. In group A there were 26 patients (7.4%) with CHF, and in group B there were 324 patients (92.6%) without this complication. Baseline clinical and demographic characteristics and in-hospital complications of the groups were assessed. In group A patients were older (67.6 ± 9.5 vs 53.7 ± 10.9 years, p < 0.0001) and there were more female patients (50% vs 15%, p < 0.00001) compared to group B. The prevalence of diabetes mellitus (58% vs 16%) and precordial ST segment depression on admission ECG (81% vs 50%) were significantly higher in group A compared to group B (p < 0.00001 and p=0.002 consecutively). In group A there was a higher rate of righ ventricular (25% vs 23%), posterior (26% vs 24%) and posterolateral myocardial infarction (19% vs 14%), but the differences were not statistically different. In group A patients had significantly higher rate of second- or third-degree AV block (46% vs 8%, p < 0.00001), cardiogenic shock (35% vs 1%, p < 0.00001) and mortality (46% vs 3%, p < 0.00001) compared to group B. In a multivariate regression analysis diabetes mellitus (p=0.0003) and precordial ST segment depression on admission ECG (p=0.002) were found as the independent predictors of in-hospital CHF in patients with acute inferior MI. CHF and ST segment depression on admission ECG were found as the independent predictors of in-hospital mortality (p < 0.00001, p=0.04 consecutively). Patients with CHF complicating acute inferior MI have more unfavorable demographic and clinical characteristics on admission, higher rate of in-hospital complications and mortality. History of diabetes mellitus and precordial ST segment depression on admission ECG have an independent predictive value for CHF in this particular group of patients.