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

Authors:
  • ASAndreas F. Schaub
    Andreas F. Schaub
  • PBPaolo Bernasconi
    Paolo Bernasconi
  • IHIrene Hösli
    Irene Hösli
  • WHWolfgang Holzgreve
    Wolfgang Holzgreve
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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: 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.