576: Evaluation of the fetal QT interval using non-invasive fetal ECG technology

Abstract

Non-invasive fetal electrocardiography (NI-FECG) is a promising alternative continuous fetal monitoring method that has the potential to allow morphological analysis of the FECG. However, there are a number of challenges associated with the evaluation of morphological parameters from the NI-FECG, including low signal to noise ratio of the NI-FECG and methodological challenges for getting reference annotations and evaluating the accuracy of segmentation algorithms. This work aims to validate the measurement of the fetal QT interval in term laboring women using a NI-FECG electrocardiogram monitor. Fetal electrocardiogram data were recorded from 22 laboring women at term using the NI-FECG and an invasive fetal scalp electrode simultaneously. A total of 105 one-minute epochs were selected for analysis. Three pediatric electrophysiologists independently annotated individual waveforms and averaged waveforms from each epoch. The intervals measured on the averaged cycles taken from the NI-FECG and the fetal scalp electrode showed a close agreement; the root mean square error between all corresponding averaged NI-FECG and fetal scalp electrode beats was 13.6 milliseconds, which is lower than the lowest adult root mean square error of 16.1 milliseconds observed in related adult QT studies. These results provide evidence that NI-FECG technology enables accurate extraction of the fetal QT interval.

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

“…Zhu et al combined adult QT annotations from different individuals and automated algorithms in order to improve the estimation of the reference annotations. This algorithm has recently been used in Behar et al (2014e) to estimate foetal QT (FQT) by merging the annotations from three medical professionals (see figure 9). We recommend using a consensus of at least three human annotations for obtaining morphological references such as FQT interval particularly given that no open SECG segmentation and signal quality algorithm exists to date.…”

“…In recent years, a handful of NI-FECG commercial monitors have appeared in the market and more competing solutions are in development Particularly interesting are two monitors that have obtained FDA clearance: the Monica AN24 monitor (Monica Healthcare, Nottingham, UK) and the Meridian M100/M1000 monitors from MindChild Medical (North Andover, MA) 6 . Both monitors have proved to be accurate in detecting FHR (Sameni et al 2009, Reinhard et al 2012, and some seminal work on extracting morphological information has shown promise for the latter monitor (Clifford et al 2011, Behar 2014. However, the studies associated with these monitors were limited in patient numbers and population size and further research is needed to address a broad range of populations and conditions.…”

“…using a lower number of, or single, abdominal channel) include adaptive filtering (Widrow et al 1975, Camps et al 2001, Behar et al 2014b, template subtraction (Cerutti et al 1986, Kanjilal et al 1997, Martens et al 2007, Ungureanu et al 2007, Kalman filtering (KF) (Sameni 2008, Zaunseder et al 2012, Gaussian processes (Niknazar et al 2013a), tensor decomposition (Niknazar et al 2012) and the combination of multiple methods (Behar et al 2014d). Refer to chapter 3 of the thesis from Behar (2014) for a detailed presentation of some of the main algorithms. Table 3 classifies these algorithms into three categories: blind source separation (BSS), adaptive filtering methods (AM) and template subtraction methods (TS).…”

“…In a study by Oudijk et al (2004), a significant shortening of the QT interval has been shown to be associated with intrapartum hypoxia resulting in metabolic acidosis, whereas in normal labour none of such changes do occur. In Behar et al (2014e) the authors showed the possibility to recover the foetal QT from the NI-FECG. Three clinicians manually annotated the foetal QT on the NI-FECG and FSE from 22 labouring women.…”