Joachim Behar, DPhil candidate, Dept. Eng. Sci. University of Oxford Current issues in healthcare 5. Foetal Electrocardiography Centre for Doctoral Training in Healthcare Innovation

The patient

Current foetal monitoring systems  Goal: assessing the foetus well being. Early detection of cardiac abnormalities might help medications and precaution at delivery  Doppler ultrasound routinely used  Why using ECG? Study of the morphology and temporal parameters of the FECG could provide valuable information to assess the foetus well- being.

The Problem  History  Observed by M Cremer (1906)  Two methods for FECG  Scalp ECG  Abdominal ECG  The non invasive ECG is constituted by  Foetal brain activity  Myography (muscle signal)  Movement artefacts  Mixture of FECG and MECG  (Multiple pregnancy)  Working in...  Time domain?  Frequency domain?

The Problem  Working in the time domain ? Fig: 3 seconds of FECG and MECG mixtures obtained using abdominal electrodes.

The Problem  Working in the frequency domain ? Fig: Power spectral density distribution using the burg method (order 20) and for 5min of scalp electrode ECG and 5min adult ECG.

Current situation  Many attempt at separating the FECG from the MECG using various methods based on filtering, blind source separation, event synchronous canceller.  But “the analysis of foetal ECGs is still in its infancy…” (Sameni et al 2010)  The main problem is to extract t the FECG waveform…  … and prove that this is what you are actually looking for!  … and prove that the method is working on a sufficiently large database (by opposition to one subject).

What can we do to improve this?  Separation of the foetus ECG waveform from the mixture  And how do we scientifically prove that what we are extracting is the actual FECG waveform? (gold standard?)  …

References  A Review of Fetal ECG Signal Processing; Issues and Promising Directions. Reza Sameni1and Gari D. Cliord. The Open Pacing, Electrophysiology & Therapy Journal (TOPETJ), vol. 3, pp. 4-20, November  Martens, S.M.M., Rabotti, C., Mischi, M., and Sluijter, R.J. (2007). A robust fetal ECG detection method for abdominal recordings. Physiol. Meas., 28:373–388.  Noninvasive Fetal Electrocardiogram Extraction: Blind Separation Versus Adaptive Noise Cancellation Vicente Zarzoso, Associate Member, IEEE and Asoke K. Nandi*, Senior Member, IEEE  etc.

May the force be with you!