title: Doppler flow characteristics in the main pulmonary artery and the LA/Ao ratio before and after ductal closure in healthy newborns.
abstract: Echo-Doppler (ED) techniques were used to estimate the time of closure of the ductus arteriosus in 30 normal neonates. We found that after birth there was a left-to-right (L-R) shunt through the ductus, which disappeared within 14 hours in 50% of the neonates investigated. Furthermore, patency of the ductus was not associated with a murmur. After closure of the ductus there was a significant diminution of the echocardiographically determined left atrium/aortic (LA/Ao) ratio, which was used as a measure of the L-R shunt.
mesh_terms: D001775:Blood Circulation; D004373:Ductus Arteriosus / Q000502:physiology*; D004374:Ductus Arteriosus, Patent / Q000175:diagnosis; D004452:Echocardiography; D006801:Humans; D007231:Infant, Newborn; D011651:Pulmonary Artery / Q000502:physiology*; D014463:Ultrasonography