The purpose of this study was to define the sequential changes in global and regional right ventricular function, using equilibrium gated radionuclide angiography, following transmural inferior myocardial infarction (IMI) and associated ischemic right ventricular involvement. 24 patients with IMI underwent radionuclide angiography within 72 hours of onset of chest pain; subsequent studies were done at 13 +/- 5 days and at 6 +/- 2 months. Scintigraphic evidence of ischemic right ventricular involvement was defined by depression of right ventricular ejection fraction (less than 40%) and regional wall motion abnormalities (hypo-a-dyskinesia of right ventricular free wall). Significant improvement of global right ventricular ejection fraction was observed in 15 patients at the second study, and in 21 patients at the third study. Right ventricular regional wall motion showed similar improvement from the initial to the final studies. Significant changes in right ventricular function occurred without concurrent changes in global and regional left ventricular ejection fraction. We concluded that patients with IMI and ischemic right ventricular involvement show frequently improvement of global and regional right ventricular function over time. This changes tend to occur early and without significant modifications in left ventricular function. The good prognosis observed in our patients, despite the high incidence of in hospital complications, might be related to the improvement of right ventricular function.