Right Ventricular Dysfunction in Acute Inferoposterior Myocardial Infarction: An Echocardiographic and Isotopic Study

Abstract

We analyzed right ventricular (RV) regional wall motion by two-dimensional echocardiographic (2D echo) and multigated acquisition radionuclear (MUGA) studies in 104 patients with acute inferoposterior myocardial infarction (AIPMI). Sixty-eight patients (65 percent) had 2D echo RV regional wall motion abnormalities (RV dysfunction(RVD) group) while 36 patients showed no 2-D echo RV regional wall motion abnormalities (no-RVD group). The RVD group had a higher incidence of jugular venous engorgement (p less than 0.05), Kusmaul's sign, (p less than 0.05) complete atrio-ventricular block (p less than 0.05), and in-hospital death (p less than 0.02). The RVD group had significantly higher 2-D echo RV end-systolic dimensions (p less than 0.005) and lower values of percentage of fractional shortening (%FS) (p less than 0.005) in the long and short axis of the RV four-chamber view than patients in the no-RVD group and a control group of 20 patients with normal hearts. There was no statistical significant difference in the 2-D echo RV end-diastolic dimensions among the three groups. Patients in the RVD group had a lower MUGA derived RV ejection fraction (EF) than patients in the no-RVD and control groups (26.5 +/- 13.2 vs. 46.3 +/- 7 and vs. 50.6 +/- 4, respectively; p less than 0.05). RVD was diagnosed by both 2-D echo and MUGA in 60 of 104 patients (57.7 percent) with a sensitivity for 2-D echo of 92 percent and 79 percent specificity (when compared to the MUGA study). The predictive value for a positive test was 88 percent and for a negative test 86 percent. The accuracy was 87.5 percent. Recognition of regional wall motion abnormalities by 2-D echo permits a prompt and accurate bedside identification of right ventricular dysfunction (RVD) within the first 72 hours of clinical onset. An enlarged RV 2D echo end-diastolic dimension was not a sensitive parameter for the diagnosis of this pathology, whereas an increased end-systolic RV diameter and decreased RV %FS were better indicators of RV dysfunction in patients with acute inferoposterior wall myocardial infarction.