title: Normal and abnormal diameter pulse waveforms in the fetal inferior vena cava.
abstract: OBJECTIVE
  To study the diameter pulse waveforms (DPWs) recorded noninvasively from the fetal inferior vena cava (IVC) in human fetuses.
  
  
  METHODS
  We studied 90 normal fetuses (20 to 40 weeks), ten fetuses with abnormalities of cardiac structure, and seven fetuses with arrhythmia. A paired ultrasonic phase-locked echo tracking system was used to follow the movement of diametrically opposite points of the IVC.
  
  
  RESULTS
  The four component (A, X, V, Y) waves of the DPW were identified. In the normal group, there was an increase in the depth of X and Y nadirs. The abnormal group was divided into two subgroups. In 12 fetuses (five pulmonary stenosis, seven arrhythmia) there was a high pulsatile pattern with deep nadir from the A peak to X trough so that the pulsatility of the waveform appeared increased. The cause of the high pulsatility was due to a marked change of intraatrial pressure. In five fetuses with tricuspid regurgitation, this change was shallow and the pulsatility appeared reduced. Clinical outcome was significantly worse in the low pulsatile subgroup.
  
  
  CONCLUSIONS
  The low pulsatility waveform may indicate depressed myocardial function. Measuring the DPW provides a simple method for obtaining important information about fetal cardiac performance.
authors.affiliation: Department of Obstetric & Gynecology, Tokai university school of medicine, Boseidai, Isehara-city, Kanagawa, 259-1193, Japan. mor11@is.icc.u-tokai.ac.jp
authors.forename: Akira
authors.initials: A
authors.lastname: Mori
authors.forename: Noa
authors.initials: N
authors.lastname: Uchida
authors.forename: Akifumi
authors.initials: A
authors.lastname: Inomo
authors.forename: Yoko
authors.initials: Y
authors.lastname: Ishiguro
authors.forename: Togo
authors.initials: T
authors.lastname: Atsuko
authors.forename: Mikami
authors.initials: M
authors.lastname: Mikio
mesh_terms: D001145:Arrhythmias, Cardiac / Q000000981:diagnostic imaging / Q000196:embryology / Q000503:physiopathology; D001775:Blood Circulation / Q000502:physiology*; D004452:Echocardiography; D005260:Female; D005318:Fetal Heart / Q000002:abnormalities* / Q000000981:diagnostic imaging; D006801:Humans; D011247:Pregnancy; D011256:Pregnancy Outcome; D011674:Pulse; D012016:Reference Values; D016216:Ultrasonography, Prenatal; D014682:Vena Cava, Inferior / Q000196:embryology* / Q000502:physiology