Fetal autonomic brain age scores, segmented heart rate variability analysis, and traditional short term variability.

Dirk Hoyer,Jens Haueisen,Kathrin Kumm,Anja Rudolph,Liviu Moraru,Ulrike Wallwitz,Theresa Gã¶Tz,Alexander Schmidt,Ekkehard Schleuãÿner,Isabelle Kynass,Samuel Nowack,Janine Tegtmeyer,Florian Tetschke,Otto W Witte,Uwe Schneider,Eva-Maria Kowalski,Franziska Bode

doi:10.3389/fnhum.2014.00948

Abstract

Disturbances of fetal autonomic brain development can be evaluated from fetal heart rate patterns (HRP) reflecting the activity of the autonomic nervous system. Although HRP analysis from cardiotocographic (CTG) recordings is established for fetal surveillance, temporal resolution is low. Fetal magnetocardiography (MCG), however, provides stable continuous recordings at a higher temporal resolution combined with a more precise heart rate variability (HRV) analysis. A direct comparison of CTG and MCG based HRV analysis is pending. The aims of the present study are: (i) to compare the fetal maturation age predicting value of the MCG based fetal Autonomic Brain Age Score (fABAS) approach with that of CTG based Dawes-Redman methodology; and (ii) to elaborate fABAS methodology by segmentation according to fetal behavioral states and HRP. We investigated MCG recordings from 418 normal fetuses, aged between 21 and 40 weeks of gestation. In linear regression models we obtained an age predicting value of CTG compatible short term variability (STV) of R2 = 0.200 (coefficient of determination) in contrast to MCG/fABAS related multivariate models with R2 = 0.648 in 30 min recordings, R2 = 0.610 in active sleep segments of 10 min, and R2 = 0.626 in quiet sleep segments of 10 min. Additionally segmented analysis under particular exclusion of accelerations (AC) and decelerations (DC) in quiet sleep resulted in a novel multivariate model with R2 = 0.706. According to our results, fMCG based fABAS may provide a promising tool for the estimation of fetal autonomic brain age. Beside other traditional and novel HRV indices as possible indicators of developmental disturbances, the establishment of a fABAS score normogram may represent a specific reference. The present results are intended to contribute to further exploration and validation using independent data sets and multicenter research structures.

Highlights

Prenatal risk factors can permanently change the fetal brain development and are associated with diseases in later age
SUBJECTS AND DATA AQUISITION From the study database of the Biomagnetic Center, Department of Neurology, and Department of Obstetrics, both Jena University Hospital, recordings of 418 normal singleton fetuses, aged between 21 and 40 weeks of gestation (WGA), healthy according to standard obstetric observation methods, single recording in a non-stress situation were included
We have demonstrated a strong relationship between those heart rate variability (HRV) indices and fetal maturation age (Hoyer et al, 2009)

Summary

Introduction

Prenatal risk factors can permanently change the fetal brain development and are associated with diseases in later age. Adverse influences during fetal development that became permanently programmed can increase the postnatal risk for cardiovascular, metabolic, hyperkinetic, cognitive, learning and behavioral disorders (e.g., Barker, 1998, 2002; Barker et al, 2002; O’Keeffe et al, 2003; Van den Bergh et al, 2005). The associated heart rate patterns (HRP) are one of the few signals that can be obtained non-invasively from the fetus, and heart rate variability (HRV) analysis is uniquely suited to assess the fetal functional autonomic brain development. Fetal HRP provide quantitative information about sympathetic and vagal activation, fetal behavioral states, and fetal movements (Nijhuis et al, 1982; Van Leeuwen et al, 1999; David et al, 2007; Hoyer et al, 2009; Schmidt et al, 2014)

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