Doppler echocardiography was used to estimate pulmonary artery (PA) pressure in 45 adult patients with various kinds of heart disease and the patterns were compared with those of 32 normal control subjects. Doppler signals obtained in the right ventricular (RV) outflow tract just proximal to the pulmonary valve and electrocardiogram were recorded simultaneously. Doppler velocity time intervals were measured as follows: RV preejection period, acceleration time from the onset of the RV ejection flow velocity to the peak, and RV ejection time. Thirty patients had PA hypertension and 16 patients had a low cardiac index. The best correlation with PA pressure was achieved by the RV preejection period/acceleration time index (r = 0.89 vs mean pressure). Sensitivity and specificity for predicting PA hypertension were 93% and 97%, respectively. Acceleration time correlated best with the logarithm of PA mean pressure (r = 0.88). Patients were separated into 2 groups according to cardiac index. In those patients with a cardiac index of less than 2.5 liters/min/m2, both RV preejection period/acceleration time and acceleration time were significantly correlated with PA mean pressure (r = 0.87) and log (PA mean pressure) (r = -0.87), respectively. However, the slope of the regression line for acceleration time and log (PA mean pressure) was significantly steeper than that for patients with a cardiac index of greater than or equal to 2.5 liters/min/m2 (p less than 0.05), whereas the relation between RV preejection period/acceleration time and PA mean pressure in the 2 groups could not be differentiated statistically from each other. Other intervals and ratios were less quantitative because of late systolic turbulent flow and individual variability.(ABSTRACT TRUNCATED AT 250 WORDS)