Simultaneous right heart catheterization and radionuclide ventriculography were performed in 27 patients with a wide range of chronic obstructive pulmonary disease. Central hemodynamics and radionuclide studies were done at rest and during exercise. In the resting state the right ventricular ejection fraction (RVEF) was in the normal range (43.3 +/- 6%). During exercise a significant (p less than 0.001) decrease of RVEF to 38.8 +/- 6.7% occurred. The pulmonary artery mean pressures were 19.9 +/- 3.8 at rest. During exercise a significant (p less than 0.001) increase to 41 +/- 9.8 mm Hg occurred. There was a linear relationship between pulmonary pressures and RVEF during exercise in patients with pulmonary artery pressures not exceeding 35 mm Hg. In patients with right ventricular end-diastolic wall thickness greater than or equal to 6 mm a curvilinear relationship between these parameters could be observed with a flattening of the curve at higher pressures (greater than 35 mm Hg) and lower ejection fractions (less than 35% RVEF). Radionuclide ventriculography cannot substitute for right heart catheterization. Echocardiography is useful for interpretation of right ventricular ejection fractions in advanced chronic obstructive pulmonary disease.