A practical guide to non-invasive foetal electrocardiogram extraction and analysis

Abstract

Non-Invasive foetal electrocardiography (NI-FECG) represents an alternative foetal monitoring technique to traditional Doppler ultrasound approaches, that is non-invasive and has the potential to provide additional clinical information. However, despite the significant advances in the field of adult ECG signal processing over the past decades, the analysis of NI-FECG remains challenging and largely unexplored. This is mainly due to the relatively low signal-to-noise ratio of the FECG compared to the maternal ECG, which overlaps in both time and frequency. This article is intended to be used by researchers as a practical guide to NI-FECG signal processing, in the context of the above issues. It reviews recent advances in NI-FECG research including: publicly available databases, NI-FECG extraction techniques for foetal heart rate evaluation and morphological analysis, NI-FECG simulators and the methodology and statistics for assessing the performance of the extraction algorithms. Reference to the most recent work is given, recent findings are highlighted in the form of intermediate summaries, references to open source code and publicly available databases are provided and promising directions for future research are motivated. In particular we emphasise the need and specifications for building a new open reference database of NI-FECG signals, and the need for new algorithms to be benchmarked on the same database, employing the same evaluation statistics. Finally we motivate the need for research in NI-FECG to address morphological analysis, since this represent one of the most promising avenues for this foetal monitoring modality.

Noninvasive fetal electrocardiography for the detection of fetal arrhythmias

“…Noninvasive fetal electrocardiography (NI‐FECG) is a promising noninvasive fetal diagnosis and monitoring alternative, which presents a number of advantages: low cost, possibility of local analysis (no need of long distance referral for pregnant women), information on atrial and ventricular activity, motion estimation, and possibility of continuous long‐term remote monitoring. The results of recent studies have shown the ability of the NI‐FECG to provide an accurate estimate of the fetal heart rate . However, to date, the clinical usability of NI‐FECG has rarely been studied.…”

“…The results of recent studies have shown the ability of the NI-FECG to provide an accurate estimate of the fetal heart rate. [11][12][13][14][15][16] However, to date, the clinical usability of NI-FECG has rarely been studied. This work investigates the feasibility and interest for a fetal Holter ECG device in the context of fetal ARR detection.…”

The effects of asymmetric volume conductor modeling on non-invasive fetal ECG extraction

“…NI-FECG demonstrates several advantages over ultrasound based cardiotocography (CTG) in that it is a passive modality suitable for long term use and may provide novel physiological information in addition to FHR [4]- [6]. As the ECG waveform aims to represent the magnitude and temporal characteristics of electrical currents within the cardiac muscle, morphological analysis of NI-FECG recordings has been proposed for identifying signs of fetal distress such as hypoxia and intrauterine growth restriction (IUGR) [7]- [9]. The process of morphological analysis can be divided into two distinct phases: 1) Extraction -the process of extracting a fetal ECG waveform from noisy single or multi-channel recordings and 2) Analysis -the process of analyzing features of the extracted ECG waveform to assess physiological state.…”

Linear phase FIR filter to compute fetal heart rate variability

“…A singlelead configuration is helpful for implementa-tion in a mini health care unit, making it suitable for ambulatory and long-term monitoring. [9].…”