title: Respiratory sinus arrhythmia in growth restricted fetuses with normal Doppler hemodynamic indices.
abstract: BACKGROUND
  The autonomic behavior of growth-restricted fetuses at different evolving hemodynamic stages has not been fully elicited.
  
  
  OBJECTIVE
  To analyze the respiratory sinus arrhythmia (RSA) of growth-restricted fetuses that despite this severe condition show normal Doppler hemodynamics.
  
  
  METHODS
  10 growth-restricted fetuses (FGR group) with normal arterial pulsatility indices (umbilical, uterine, middle cerebral, ductus venosus and aortic isthmus), and 10 healthy fetuses (Control group), 32-37weeks of gestation.
  
  
  METHODS
  B-mode ultrasound images for visualizing fetal breathing movements (FBM) or breathing akinesis (FBA), and the simultaneous RR-interval time series from maternal abdominal ECG recordings were obtained. The root-mean-square of successive differences of RR-intervals (RMSSD) was considered as a RSA-related parameter among the instantaneous amplitude of the high-frequency component (AMPHF) and its corresponding instantaneous frequency (IFHF), both computed by using empirical mode decomposition. Mean fetal heart-periods and RSA-related parameters were assessed during episodes of FBM and FBA in 30s length windows.
  
  
  RESULTS
  FGR and Control groups presented RSA-related fluctuations during FBM and FBA. Also, both groups showed significant higher (p<0.001) values for the mean heart-period, RMSSD and AMPHF during FBM. No-significant differences (p>0.05) were found for the IFHF regardless of breathing activity (FBM vs. FBA).
  
  
  CONCLUSIONS
  Growth-restricted fetuses without evident hemodynamic compromise exhibit a preserved autonomic cardiovascular regulation, characterized by higher values of RSA and mean heart-period in the presence of FBM. This physiological response reflects a compensatory strategy that may contribute to preserve blood flow redistribution to vital organs.
authors.affiliation: Laboratorio de Investigación en Fisiología Humana (LIFH), Departamento de Ciencias de la Salud, Universidad Autónoma Metropolitana Unidad Iztapalapa (UAM-I), 09340 México D.F., México; Programa de Doctorado en Ingeniería Biomédica, División de Ciencias Básicas e Ingeniería, UAM-I, 09340 México D.F., México. Electronic address: ronald.arias@gmail.com.
authors.forename: R
authors.initials: R
authors.lastname: Arias-Ortega
authors.affiliation: Ingeniería de Fenómenos Fisiológicos Perinatales, Departamento de Ingeniería Eléctrica, UAM-I, 09340 México D.F., México.
authors.forename: J C
authors.initials: JC
authors.lastname: Echeverría
authors.affiliation: Unidad de Investigación de Medicina Materno Fetal, del Departamento de Medicina Fetal del Instituto Nacional de Perinatología (INPer), 11000 México D.F., México.
authors.forename: M
authors.initials: M
authors.lastname: Guzmán-Huerta
authors.affiliation: Unidad de Investigación de Medicina Materno Fetal, del Departamento de Medicina Fetal del Instituto Nacional de Perinatología (INPer), 11000 México D.F., México.
authors.forename: L
authors.initials: L
authors.lastname: Camargo-Marín
authors.affiliation: Laboratorio de Investigación en Fisiología Humana (LIFH), Departamento de Ciencias de la Salud, Universidad Autónoma Metropolitana Unidad Iztapalapa (UAM-I), 09340 México D.F., México.
authors.forename: M J
authors.initials: MJ
authors.lastname: Gaitán-González
authors.affiliation: Unidad de Investigación de Medicina Materno Fetal, del Departamento de Medicina Fetal del Instituto Nacional de Perinatología (INPer), 11000 México D.F., México.
authors.forename: H
authors.initials: H
authors.lastname: Borboa-Olivares
authors.affiliation: Programa de Doctorado en Ingeniería Biomédica, División de Ciencias Básicas e Ingeniería, UAM-I, 09340 México D.F., México.
authors.forename: E
authors.initials: E
authors.lastname: Portilla-Islas
authors.affiliation: Centro de Investigación Materno Infantil del Grupo de Estudios al Nacimiento (CIMIGen), 09890 México D.F., México.
authors.forename: S
authors.initials: S
authors.lastname: Camal-Ugarte
authors.affiliation: Centro de Investigación Materno Infantil del Grupo de Estudios al Nacimiento (CIMIGen), 09890 México D.F., México.
authors.forename: C
authors.initials: C
authors.lastname: Vargas-García
authors.affiliation: Ingeniería de Fenómenos Fisiológicos Perinatales, Departamento de Ingeniería Eléctrica, UAM-I, 09340 México D.F., México.
authors.forename: M R
authors.initials: MR
authors.lastname: Ortiz
authors.affiliation: Laboratorio de Investigación en Fisiología Humana (LIFH), Departamento de Ciencias de la Salud, Universidad Autónoma Metropolitana Unidad Iztapalapa (UAM-I), 09340 México D.F., México. Electronic address: rgc@xanum.uam.mx.
authors.forename: R
authors.initials: R
authors.lastname: González-Camarena
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D005260:Female; D005317:Fetal Growth Retardation / Q000000981:diagnostic imaging* / Q000503:physiopathology; D006439:Hemodynamics; D006801:Humans; D011247:Pregnancy; D065809:Respiratory Sinus Arrhythmia; D018608:Ultrasonography, Doppler; D016216:Ultrasonography, Prenatal
keywords: Autonomic vagal activity; Fetal breathing movements; Fetal growth restriction; Heart rate variability; Respiratory sinus arrhythmia