Thirty-two neonates and infants with pulmonary atresia with ventricular septal defect were initially investigated with cross-sectional and spectral Doppler echocardiography and Doppler color flow mapping. All 32 had subsequent correlative angiography. This demonstrated that 24 infants had adequate-sized right and left pulmonary arteries (19 confluent, 5 nonconfluent). Of the five infants with nonconfluent pulmonary arteries, four had bilateral ductus arteriosus and one had a single left-sided ductus with anomalous origin of the right pulmonary artery from the ascending aorta. Nineteen infants had confluent pulmonary arteries, all of which were supplied by a single ductus. Eight infants had complete absence of or inadequate pulmonary arteries; all had multiple aortopulmonary collateral vessels arising from the descending aorta. The presence of adequate-sized right and left pulmonary arteries was correctly predicted in 21 of 24 infants by cross-sectional echocardiography alone and in all 24 by Doppler color flow mapping. Confluence of the right and left pulmonary arteries was predicted by cross-sectional imaging in 14 of the 19 infants in whom it occurred, and by Doppler color flow mapping in all 19 infants. The precise definition of the pulmonary blood supply was correctly predicted by Doppler color flow mapping in 16 of the 19 infants with confluent pulmonary arteries and a single ductus. However, in three infants in this group, Doppler color flow mapping made a false diagnosis of multiple aortopulmonary collateral vessels.(ABSTRACT TRUNCATED AT 250 WORDS)