Effects of anteroseptal myocardial infarction on systolic and diastolic filling function of the right ventricle

: To assess the effects of wall motion abnormalities of the anterior left ventricle and interventricular septum on right ventricular (RV) systolic and diastolic filling function, multiple-gated radionuclide angiography was performed at rest in 53 patients with previous anteroseptal myocardial infarction and 14 normal subjects. There were 26 patients with left ventricular ejection fraction (LVEF) greater than or equal to 45% (group 1) and 27 with LVEF less than 45% (group 2). Six measurements were obtained simultaneously in both ventricles: 1) EF, 2) peak ejection rate, 3) duration of systole, 4) peak filling rate, 5) time to the peak filling rate, and 6) ratio of the peak filling rate to the peak ejection rate. The mean RV ejection fraction and the peak ejection rate in groups 1 and 2 were similar to those in the normal subjects. The ratio of the peak RV filling rate to the peak RV ejection rate, a sensitive indicator of diastolic filling function, decreased significantly in group 1 (0.61 +/- 0.15, p less than 0.02) and group 2 (0.59 +/- 0.15, p less than 0.02) as compared with that in the normal subjects (0.74 +/- 0.14). This indicates an impairment of early diastolic RV filling compared with RV systolic function. Thus, RV systolic function appears to be normally maintained even when anteroseptal wall motion is severely impaired; however, even in the presence of mild anteroseptal wall motion abnormality, RV filling may be impaired without reduced RV systolic function.