Serial evaluation of right ventricular dysfunction associated with acute inferior myocardial infarction

Right ventricular (RV) function was evaluated serially by multigated blood pool imaging in 18 patients with RV dysfunction associated with acute inferior myocardial infarction. Radionuclide ventriculograms were performed on all patients within 18 hours of chest pain and again at 10 days. In addition, 15 of 18 patients had rest and exercise radionuclide ventriculograms at 3 months. The mean resting right ventricular ejection fractions (RVEF) at admission, 10 days, and 3 months in these patients was 31.8 +/- 12.6% (SD), 46.9 +/- 11.2% (p less than 0.05), and 44.5 +/- 10.2% (p less than 0.05), while the left ventricular ejection fractions were 55.9 +/- 10.6%, 57.9 +/- 13.3%, and 53.1 +/- 11.2% (p = ns). The 3-month exercise radionuclide ventriculogram demonstrated an increase in RVEF greater than 5% in 6 of 15 patients. In eight catheterized patients, neither the location nor the severity of coronary artery narrowing nor the presence of collaterals correlated with the RV exercise response. Improvement in RV function over a 10-day interval following acute inferior myocardial infarction suggests the presence of significant reversible right ventricular dysfunction during the acute phase.