To determine the usefulness of systemic venous flow patterns in patients with mild/moderate right ventricular hypertension, 17 patients with isolated mild/moderate pulmonic stenosis and 17 age-matched normal children were evaluated with pulsed Doppler echocardiography. Tricuspid valve, superior vena caval, and hepatic vein pulsed Doppler recordings were obtained with simultaneous respirometry and electrocardiography. Peak velocities and velocity-time integrals were measured for Doppler signals corresponding with ventricular systole, ventricular diastole, ventricular end systole, and atrial systole. The groups were similar in weight, heart rate, tricuspid inflow Doppler echocardiograms, and cardiac indexes. Compared with normal subjects, patients showed changes in respiratory variation for some superior vena caval and hepatic vein indexes. In addition, hepatic vein measurements made at ventricular end systole were significantly lower and measurements made at atrial systole were significantly higher in patients than in normal subjects. These changes in systemic venous flow patterns may provide a sensitive indicator of early right-sided heart dysfunction.