Spectral Analysis of Fetal Heart Rate Variability in Fetuses with Supraventricular Extrasystoles

Abstract

Objective: Fetal heart rate (FHR) variability is an important indicator of fetal well-being. In fetal tachyarrhythmias, however, visual analysis of FHR variability is limited. We therefore applied power spectral analysis of FHR to evaluate the fetal state. Methods: Fetal R-R intervals were detected by means of an external ECG in 3 fetuses with supraventricular extrasystoles after cardiac malformations had been excluded by fetal echocardiography. Using an autoregressive model, power spectral densities were calculated from 20 consecutive 256-beat segments for the following frequency bands: <0.03 Hz (very low frequency), 0.03–0.069 Hz (low frequency; LF), 0.07–0.129 Hz (mid-frequency) and 0.13–1.0 Hz (high frequency; HF). Results: The FHR variability in fetal supraventricular extrasystoles mainly resulted from the HF component (63.91 ± 6.97%). The sympatho-vagal balance (LF/HF) was decreased in the tracings with extrasystoles (0.13). Conclusion: The analysis of FHR variability in fetal supraventricular extrasystoles revealed an imbalance between sympathetic and parasympathetic regulation.

Characterization of Fetal Arrhythmias by Means of Fetal Magnetocardiography in Three Cases of Difficult Ultrasonographic Imaging

“…27 were in contrast with the values and trends already available. 34 Although in fetal studies the significance of such parameters is still highly speculative, the outcome of the present study might suggest a possible unbalance between sympathetic and parasympathetic innervations, as already indicated in another study 30 ; this transitory unbalance might play a pathogenetic role in the occurrence of fetal arrhythmias.…”

“…Spectral analysis of fetal heart rate variability may help in the classification of arrhythmias and in the assessment of the functional state of the fetal autonomous nervous system (ANS): 30–32 a variability >5 beats/min is generally considered an indicator of fetal well‐being.…”

“…33−35 However, the criteria used for HRV analysis in adults cannot be applied in fetal studies in a straightforward manner, and the significance of HRV parameters is still under investigation, and only suggestions have been given of their possible relationship with the development of the ANS during pregnancy. 30,31 The dependence of HRV parameters on variables like fetal age, activity, and breathing has also been investigated, whereas the question on what bandwidths would be more appropriate to assess the fetal autonomic state or development is still open. 32,34 Time and frequency HRV parameters are shown in Table I, and, in particular, LF:HF ratios PACE,Vol.…”

Nonlinear properties of vagal and sympathetic modulations of heart rate variability in ovine fetus near term

“…This requires a deeper understanding of the physiological meaning of fHRV complexity, including how its linear and nonlinear properties are modulated by sympathetic and vagal activity of the autonomic nervous system (ANS). Understanding fHRV dynamics during physiological (e.g., sleep states dependent changes) and pathophysiological (e.g., asphyxia) conditions has evolved over the past two decades, propelled by analyses of the linear aspects of fHRV in human and ovine fetuses (4,11,16,20,29,32). However, characterization of the linear fHRV properties is fundamentally limited in its power to describe the nonlinear structure of the underlying sympathovagal interactions (12,14).…”

Fetal and offspring arrhythmia following exposure to nicotine during pregnancy

“…Experimental and clinical studies have shown arrhythmia in fetuses (Clancy et al, 2007;Srinivasan and Strasburger, 2008;Zhao et al, 2008). Most of previous studies on fetal arrhythmia were related to abnormal development (Zhao et al, 2008;Hahurij et al, 2008;Troeger et al, 2003), only a few studies determined environmental eff ects on fetal arrhythmia (Quigley et al, 1979;Habek, 2007). Patterns of fetal arrhythmia found in utero in previous studies were either tachycardia or bradycardia (Quigley et al, 1979;Clancy et al, 2007).…”