Noninvasive estimation of pulmonary artery pressure is an important component of cardiac ultrasound studies. A number of methods are available for estimation of pulmonary pressure, each with varying degrees of reported accuracy. To assess feasibility and accuracy, noninvasive pulmonary artery pressure estimates were performed in infants and children at the time of catheterization. Patients were examined prospectively until there were 50 patients, in whom each of six methods for estimation of pulmonary pressure had been accomplished. All patients had tricuspid and pulmonary regurgitation of less than severe degree and no structural, flow, or electrocardiographic abnormality known to compromise the six methods. Systolic pressure was estimated by the Burstin method and also from peak tricuspid regurgitation velocity. Mean pressure was estimated by acceleration time divided by ejection time from waveforms obtained from the right ventricular outflow tract and main pulmonary artery. Diastolic pressure was estimated by systolic time intervals and from end-diastolic pulmonary regurgitation velocity. Noninvasive estimates were compared with simultaneous or nearly simultaneous catheterization measurements. For systolic pressure Burstin estimates were accomplished in 89% with high accuracy (r = 0.97). Tricuspid regurgitation velocities were recorded in 82%, also with high accuracy (r = 0.96). Waveforms for mean pressure estimation were recorded in 98% to 100% of patients. Those from the right ventricular outflow tract corresponded well with catheterization pressures (r = 0.94), whereas those recorded from the main pulmonary artery offered poor prediction of pulmonary pressure (r = 0.63). Systolic time interval measurements were accomplished in only 65% and did not correlate highly with catheterization (r = 0.84). Diastolic pressure estimates based on pulmonary regurgitation velocity were recorded in 98% of subjects with high accuracy (r = 0.96). Each method had advantages and disadvantages. The Burstin method was accurate but technically demanding and is reported to be limited by heart rate and significant right-sided regurgitation. Peak tricuspid velocities proved unexpectedly difficult to record in some patients but when successful, provided excellent prediction of pressure. Recording of waveforms for ratios of acceleration time to ejection time proved easy, but accuracy was high only for outflow tract waveforms. Peculiarities of main pulmonary artery flow may have led to poor accuracy for ratios measured from that site. For diastolic pressure estimation, systolic time interval records were the most difficult to obtain and did not provide useful accuracy. In contrast, pulmonary regurgitation velocities were easily obtained and provided high accuracy results. This is a selected pediatric series, evaluating methods in nearly ideal circumstances.(ABSTRACT TRUNCATED AT 400 WORDS)