title: Cause of normal pulmonic velocity in fetal tetralogy of Fallot.
abstract: In 10 fetuses with tetralogy of Fallot, 9 lacked high velocity across the obstructed right ventricular outflow tract, which we conclude was due to the parallel flow circulations created by the combination of ventricular septal defect and arterial duct. The normally high resistance in the fetal pulmonary vascular system substantially exceeds the resistance of the systemic vasculature, resulting in the maintenance of right-to-left ductal flow in all 10 fetuses who had only moderate pulmonary obstruction.
authors.affiliation: Department of Pediatrics (Cardiology), University of Washington School of Medicine, Seattle, Washington 98195-6320, USA. wgg@u.washington.edu
authors.forename: Warren G
authors.initials: WG
authors.lastname: Guntheroth
authors.forename: Fred K
authors.initials: FK
authors.lastname: Forster
authors.forename: J Geoffrey
authors.initials: JG
authors.lastname: Stevenson
mesh_terms: D001783:Blood Flow Velocity / Q000502:physiology; D005260:Female; D005315:Fetal Diseases / Q000000981:diagnostic imaging / Q000503:physiopathology; D006801:Humans; D008955:Models, Cardiovascular; D010865:Pilot Projects; D011247:Pregnancy; D011651:Pulmonary Artery / Q000000981:diagnostic imaging / Q000196:embryology* / Q000503:physiopathology; D013771:Tetralogy of Fallot / Q000000981:diagnostic imaging / Q000196:embryology* / Q000503:physiopathology; D016216:Ultrasonography, Prenatal; D014694:Ventricular Outflow Obstruction / Q000000981:diagnostic imaging / Q000196:embryology* / Q000503:physiopathology