Differences in foetal heart rate variability from phonocardiography and abdominal electrocardiography

Abstract

The agreement of the phonocardiographic method to provide foetal heart rate variability (FHRV) indices equivalent to those derived from abdominal electrocardiography was tested. 15 pregnant women were recruited in order to obtain antepartum foetal phonocardiograms and abdominal electrocardiograms three minutes long. From the respective sound (SS) and electric (RR) time series, typical temporal and spectral indices of FHRV were computed and compared. Means of the SS and RR intervals were not significant (P> 0.05) and these showed a correlation r=0.98. However, the temporal indices, P(TOT), HF and LF/HF presented differences (P< 0.05), since SS values were higher. Spectral coherence decreased below 0.5 for frequencies above 0.28+ 0.07 Hz, where bands resembling maternal and foetal breathing movements were noted. Particularly above 0.28Hz, temporal and spectral FHRV indices derived from phonocardiography and electrocardiography show differences. Quality of the signal, processing techniques, and maternal and foetal respiratory factors could account to explain these.

Metric optimized gating for fetal cardiac MRI

“…The heart rate was simulated as a bounded random walk superimposed on a constant baseline: where N is a normally distributed random variable, RR 0 is the baseline heart rate, σ is the standard deviation of the beat‐to‐beat step size in milliseconds, and Δ ∈ [0,1] is the strength of the bias bounding the walk around the baseline value. Values of Δ = 0.1 and σ = 7 ms were found to give HRV that was quantitatively representative of typical fetal HRV (40, 41). The reconstruction process was tested over a range of HRV values, with 500 random simulated heart rate traces at each value.…”

“…The mean and pulsatility are normalized against the correct values. The bar denotes the typical range of fetal HRV based on reports in the literature (40, 44). [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com.]…”

Neurobehavioral assessment before birth

“…Magnetocardiography [Stinstra No unified neurobehavioral assessment method of the fetus currently exists. and Peters, 2002] and phonocardiography [Ortiz et al, 2002] techniques are being explored as options to maximize detection of the fetal R-wave, but their ultimate feasibility for use in neurobehavioral research is unknown at this time.…”

A Novel Algorithm for HRV Estimation from Short-Term Acoustic Recordings at Neck

“…Only few studies have used the PCG signal to measure HRV and the majority of these works focus on the extraction of fetal HRV by recording the acoustic signals from the abdominal maternal wall [5], [6]. To the best of author's knowledge, this study presents, for the first time, a novel algorithm to measure HRV from the acoustic signals recorded at the 1,2 The authors are with the Department of Electrical and Electronic Engineering, Imperial College London, London SW7 2AZ, U.K.…”