Echocardiographic findings in five patients with pulmonary embolism were studied. Tricuspid echocardiograms showed abnormalities in valve motion, that is a monophasic triangular wave during diastole in all the patients as well as an increased dimension of the right ventricle. An "a' dip of the pulmonary valve echocardiogram was also recognised in all five. Later tricuspid echocardiograms regained the normal M-shaped configuration. The monophasic triangular pattern of the tricuspid valve during diastole may be related to the shorter duration of tricuspid valve opening compared with that of the mitral valve. Tachycardia cannot explain this difference between tricuspid and mitral valve motion, which seems to be caused by a prolonged isovolumic relaxation time of the right ventricle resulting in a delayed opening of the tricuspid valve. These results were obtained by comparing these data with those of control subjects and patients with chronic right ventricular overloading resulting from atrial septal defect.