title: Noninvasive measurement of isovolumetric contraction time by Doppler cardiography can be substituted for fetal cardiac contractility: evaluation of a fetal lamb study.
abstract: OBJECTIVE
  The objective of this study is to clarify whether the isovolumetric contraction time obtained from Doppler cardiography (Doppler ICT) can be an index substituted for fetal cardiac contractility.
  
  
  METHODS
  In 10 pregnant ewes, fetal hypoxemia was induced by giving a variable mixture of gases. Through experiment, the Doppler ICT, pre-ejection period (PEP), and the maximum first derivative of the left ventricular pressure waveform (Max dp/dt) were simultaneously recorded every 10min. The relationship between both the Doppler ICT and PEP, and the Max dp/dt were analyzed.
  
  
  RESULTS
  A significant negative linear regression was founded between the Doppler ICT and the Max dp/dt. A significant negative linear regression was also shown between PEP and the Max dp/dt. Moreover, the regression of Max dp/dt on ICT had significantly less residual variance than the regression of Max dp/dt on PEP (p=0.0004).
  
  
  CONCLUSIONS
  In contrast to PEP, Doppler ICT is a reliable, and non-invasive index which can be substituted for fetal cardiac contractility.
authors.affiliation: Maternity and Perinatal Care Center, Oita Prefectural Hospital Bunyo 476, Oita 870-8511, Oita, Japan. satohs@oitakenbyo.jp
authors.forename: Shoji
authors.initials: S
authors.lastname: Satoh
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Yumoto
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Fujita
authors.forename: Naoko
authors.initials: N
authors.lastname: Kinukawa
authors.forename: Hitoo
authors.initials: H
authors.lastname: Nakano
mesh_terms: D000818:Animals; D015150:Echocardiography, Doppler; D005260:Female; D005318:Fetal Heart / Q000502:physiology*; D005333:Fetus / Q000502:physiology*; D009200:Myocardial Contraction; D011247:Pregnancy; D012756:Sheep