title: Antegrade late diastolic arterial blood flow in the fetus: insight into fetal atrial function.
abstract: OBJECTIVE
  The purpose of this study was to examine the presence and frequency of antegrade late diastolic arterial blood flow (ALDAF) in the fetus and to determine its contribution to cardiac output.
  
  
  METHODS
  We evaluated the presence of ALDAF in 457 fetal and 21 postnatal echocardiograms. The timing of ALDAF to the ventricular systolic Doppler recording (ALDAF-V) was compared with the mechanical atrioventricular interval and, in neonates, the electrical PR interval. Velocity time integrals of ALDAF and the ventricular systolic Doppler signals were measured, and the percent contribution of ALDAF was calculated.
  
  
  RESULTS
  ALDAF was observed in 365 of 457 studies and included all <11 weeks' gestations. Strong correlation between ALDAF-V, atrioventricular interval, and electrical PR interval suggests that ALDAF coincides with atrial contraction. ALDAF contributed substantially to cardiac output in early gestation with later decline.
  
  
  CONCLUSIONS
  ALDAF results from atrial contraction. Increasing gestational age results in less ALDAF, and reduced ALDAF contribution to cardiac output likely due to improved diastolic function.
authors.affiliation: Fetal and Neonatal Cardiology Program, Division of Cardiology, Department of Pediatrics, University of Alberta, Edmonton, AB, Canada.
authors.forename: Lisa W
authors.initials: LW
authors.lastname: Howley
authors.forename: Yuka
authors.initials: Y
authors.lastname: Yamamoto
authors.forename: Sven-Erik
authors.initials: SE
authors.lastname: Sonesson
authors.forename: Priya
authors.initials: P
authors.lastname: Sekar
authors.forename: Venu
authors.initials: V
authors.lastname: Jain
authors.forename: Tarek
authors.initials: T
authors.lastname: Motan
authors.forename: Winnie
authors.initials: W
authors.lastname: Savard
authors.forename: Brandie D
authors.initials: BD
authors.lastname: Wagner
authors.forename: Jean
authors.initials: J
authors.lastname: Trines
authors.forename: Lisa K
authors.initials: LK
authors.lastname: Hornberger
mesh_terms: D001011:Aorta / Q000502:physiology*; D016275:Atrial Function / Q000502:physiology; D002302:Cardiac Output / Q000502:physiology; D015331:Cohort Studies; D003971:Diastole / Q000502:physiology*; D015150:Echocardiography, Doppler; D005260:Female; D005333:Fetus / Q000502:physiology*; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D011247:Pregnancy; D011651:Pulmonary Artery / Q000502:physiology*; D012039:Regional Blood Flow / Q000502:physiology*; D013599:Systole / Q000502:physiology; D013997:Time Factors