Extraction of Fetal Heart Rate and Fetal Heart Rate Variability from Mother's ECG Signal
This paper describes a new method for extracting the fetal heart rate (fHR) and the fetal heart rate variability (fHRV) signal non-invasively using abdominal maternal electrocardiogram (mECG) recordings. The extraction is based on the fundamental frequency (Fourier-s) theorem. The fundamental frequency of the mother-s electrocardiogram signal (fo-m) is calculated directly from the abdominal signal. The heart rate of the fetus is usually higher than that of the mother; as a result, the fundamental frequency of the fetal-s electrocardiogram signal (fo-f) is higher than that of the mother-s (fo-f > fo-m). Notch filters to suppress mother-s higher harmonics were designed; then a bandpass filter to target fo-f and reject fo-m is implemented. Although the bandpass filter will pass some other frequencies (harmonics), we have shown in this study that those harmonics are actually carried on fo-f, and thus have no impact on the evaluation of the beat-to-beat changes (RR intervals). The oscillations of the time-domain extracted signal represent the RR intervals. We have also shown in this study that zero-to-zero evaluation of the periods is more accurate than the peak-to-peak evaluation. This method is evaluated both on simulated signals and on different abdominal recordings obtained at different gestational ages.
Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1082169Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 2437
 Camm A. J., Malik M., Bigger J. T., Breithardt G., Cerutti S., Cohen R. J., Coumel P., Fallen E. L., Kennedy H. L., Kleiger R. E., Lombardi F., Malliani A., Moss A. J., Rottman J. N., Schmidt G., Schwartz P. J., and Singer D. H., Guidelines: Heart rate variability; Standards of measurement, physiological interpretation, and clinical use; Task Force of the European Society of Cardiology and the North American Society of Pacing and Electrophysiology, European Heart Journal, 17, 354-381, 1996.
 Troeger C., Schaub A. F., Bernasconi P., Hösli I., Holzgreve W., Spectral Analysis of Fetal Heart Rate Variability in Fetuses with Supraventricular Extrasystoles, Fetal Diagnosis and Therapy,18:284- 288, 2003.
 Schneider U., Fiedler A., Liehr M., K├ñhler C., and Schleussner E., Fetal heart rate variability in growth restricted fetuses. Biomedizinische Technik (Biomedical engineering), 51(4): 248-50, 2006.
 Pincus S. M., Viscarello R. R., Approximate entropy: a regularity measure for fetal heart rate analysis. Obstetrics & Gynecology, 79(2): 249-255, 1992.
 Di Renzo G. C., Montani M., Fioriti V., Clerici G., Barnconi F., Pardini A., Indraccolo R., and Cosmi E.V., Fractal Analysis: a new method for evaluating fetal heart rate variability. Journal of perinatal medicine, 24(3): 261-269, 1996.
 Maulik D., Saini V., Zigrossi S. T., Clinical significance of short term variability computed from heart rate waveforms. Journal of perinatal medicine, 11: 243-248, 1983.
 Leeuwen P. V., Lange S., Geue D., and Grönemeyer D., Heart rate variability in the fetus: a comparison of measures. Biosignal Processing (Special Issue-Part 3), 52(1): 61-65, 2007.
 Nelson K. B., Dambrosia J. M., Ting T. Y., and Grether J. K., Uncertain value of electronic fetal monitoring in predicting cerebral palsy. New England Journal of Medicine, 334(10): 613-619, 1996.
 Richter M., Schreiber T., and Kaplan D. T. "Fetal ECG extraction with nonlinear state-space projections" IEEE Transactions on Biomedical Engineering, 45(1): 133-137, 1998.
 Barros A. K., Ohnishi N. "Fetal heart rate variability extraction by frequency tracking" Proceedings of ICA, 2001.
 Oppenheim A. V., Schafer R. W., and Buck J. R. "Discrete-Time Signal Processing" Prentice Hall, 2nd edition, 1999.