The prognosis and recovery of right ventricular systolic function in patients with hemodynamically documented right ventricular myocardial infarction (RVMI) is unclear. Therefore 27 patients who met hemodynamic criteria for RVMI were followed for at least 1 year. Four patients died within 1 year and 23 survived. Postmortem examination performed in three of the four patients showed extensive infarction of the right and left ventricles. Survivors underwent early and late follow-up resting radionuclide ventriculograms and late exercise studies. During long-term follow-up (1 to 4 years) resting radionuclide ventriculography demonstrated a significant improvement in right ventricular ejection fraction (30 ± 7% to 43 ± 8%, p < .001) and right ventricular wall motion index (2.2 ± 0.4 to 1.5 ± 0.5; p < .001) in 18 patients who survived longer than 1 year. Fourteen of these patients underwent upright bicycle exercise while off β-blocking drugs and peak radionuclide ejection fraction was acquired after anaerobic threshold was achieved. Right ventricular ejection fraction increased significantly from 41 ± 10% to 47 ± 12% (p < .001), as did the left ventricular ejection fraction (55 ± 15% to 60 ± 12%; p < .05). The direction and magnitude of change of the right ventricular ejection fraction correlated significantly with the left ventricular ejection fraction (r = .82, p < .02). Deviations from this correlation occurred in patients who had a decreased forced expiratory volume in 1 sec and an abnormal ventilatory reserve during exercise. Also, the onset of anaerobic threshold during exercise correlated with the peak exercise right ventricular ejection fraction (r = .82, p < .02). However, there was no significant correlation with the left ventricular ejection fraction. Therefore we conclude that patients with RVMI and significant left ventricular dysfunction have a poor 1 year prognosis. Otherwise, the long-term prognosis of patients who present with hemodynamically important RVMI is excellent. Furthermore, in the recovery phase, right ventricular ejection fraction increases and right ventricular functional reserve is preserved during exercise in patients not limited by angina, pulmonary disease, or left ventricular failure.