High-risk subgroup of inferior myocardial infarction: importance of anterior wall motion and right ventricular function.

To identify high-risk subgroups of inferior myocardial infarction, 75 patients presenting with their first inferior infarction were investigated by sequential gated blood pool scans. The patients were divided into four groups based on the right ventricular function (RVF) and anterior wall motion (AWM) of the left ventricle by scan at the time of admission. A second blood pool scan was performed at ten days to evaluate RV and LV function. Thirty-eight patients had cardiac catheterization before discharge and all patients were followed up for one year to determine their clinical outcome. Depressed RVF and reduced AWM were observed in 26 (35%) (Group A); depressed RVF and normal AWM were found in 20 (27%) (Group B); reduced AWM and normal RVF in 10 (13%) (Group C); and normal RVF and AWM in 19 (25%) (Group D). The mean values of biventricular function (LVEF, RVEF) in groups A, B, C, and D were (44.9 +/- 8.4%, 32.5 +/- 9.9%), (59.9 +/- 8.6%, 34.5 +/- 8.0%), (44.9 +/- 15.7%, 48.2 +/- 3.3%), and (60.4 +/- 9.1%, 51.6 +/- 10.6%), respectively, at admission. In serial measurements, LVEF did not change significantly in any group, however, RVEF improved nearly 10 points in groups A and B at 10 days. Group A also had the highest incidence (82%) of left anterior descending coronary artery involvement, and the highest mean creatine phosphokinase levels (762 +/- 318 U/l): Furthermore, group A had a high incidence of major complications during their hospital course and high mortality during the one-year follow-up. These data clearly identified group A as a high-risk subgroup of patients with inferior infarction.