title: Fetal cardiac muscle contractility decreases with gestational age: a color-coded tissue velocity imaging study.
abstract: BACKGROUND
  Present data regarding how the fetal heart works and develops throughout gestation is limited. However, the possibility to analyze the myocardial velocity profile provides new possibilities to gain further knowledge in this area. Thus, the objective of this study was to evaluate human fetal myocardial characteristics and deformation properties using color-coded tissue velocity imaging (TVI).
  
  
  METHODS
  TVI recordings from 55 healthy fetuses, at 18 to 42 weeks of gestation, were acquired at a frame rate of 201-273 frames/s for offline analysis using software enabling retrieval of the myocardial velocity curve and 2D anatomical information. The measurements were taken from an apical four-chamber view, and the acquired data was correlated using regression analysis.
  
  
  RESULTS
  Left ventricular length and width increased uniformly with gestational age. Atrioventricular plane displacement and the E'/A' ratio also increased with gestational age, while a longitudinal shortening was demonstrated.
  
  
  CONCLUSIONS
  Fetal cardiac muscle contractility decreases with gestational age. As numerous fetal- and pregnancy-associated conditions directly influence the pumping function of the fetal heart, we believe that this new insight into the physiology of the human fetal cardiovascular system could contribute to make diagnosis and risk assessment easier and more accurate.
authors.affiliation: Department of Medical Engineering, School of Technology and Health, Royal Institute of Technology, Stockholm, Sweden. nina.elmstedt@sth.kth.se
authors.forename: Nina
authors.initials: N
authors.lastname: Elmstedt
authors.forename: Kjerstin
authors.initials: K
authors.lastname: Ferm-Widlund
authors.forename: Britta
authors.initials: B
authors.lastname: Lind
authors.forename: Lars-Åke
authors.initials: LÅ
authors.lastname: Brodin
authors.forename: Magnus
authors.initials: M
authors.lastname: Westgren
mesh_terms: D000818:Animals; D018618:Echocardiography, Doppler, Color / Q000379:methods*; D054459:Elasticity Imaging Techniques / Q000379:methods*; D005260:Female; D047109:Fetal Development / Q000502:physiology*; D005318:Fetal Heart / Q000000981:diagnostic imaging* / Q000502:physiology*; D005865:Gestational Age; D006801:Humans; D009200:Myocardial Contraction / Q000502:physiology*; D011247:Pregnancy