A systematic review of cardiac time intervals utilising non-invasive fetal electrocardiogram in normal fetuses

Vinayak Smith,Fabricio Da Silva Costa,Amrish Nair,Diane Ansermet,Senthuran Arunthavanathan,Euan Morrison Wallace

doi:10.1186/s12884-018-2006-8

Vinayak Smith, Fabricio Da Silva Costa + Show 4 more

Open Access

https://doi.org/10.1186/s12884-018-2006-8

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Abstract

BackgroundNon-invasive fetal electrocardiogram (NIFECG) is an evolving technology in fetal surveillance which is attracting increasing research interest. There is however, only limited data outlining the reference ranges for normal cardiac time intervals (CTIs). The objective of our group was to carry out a systematic review to outline normal fetal CTIs using NIFECG.MethodsA systematic review of peer reviewed literature was performed, searching PUBMED,Ovid MEDLINE and EMBASE. The outcomes of interest included fetal CTIs (P wave duration, PR interval, QRS duration and QT interval) and a descriptive summary of relevant studies as well. The outcomes were grouped as early pre-term (≤ 32 weeks), moderate to late pre-term (32–37 weeks) and term (37–41 weeks).Results8 studies were identified as suitable for inclusion. Reference ranges of CTIs were generated. Both PR interval and QRS duration demonstrated a linear correlation with advancing gestation. Several studies also demonstrated a reduction in signal acquisition between 27 and 32 weeks due to the attenuation by vernix caseosa. In this group, both the P wave and T waves were difficult to detect due to signal strength and interference.ConclusionNIFECG demonstrates utility to quantify CTIs in the fetus, particularly at advanced gestations. Larger prospective studies should be directed towards establishing reliable CTIs across various gestations.

Highlights

Non-invasive fetal electrocardiogram (NIFECG) is an evolving technology in fetal surveillance which is attracting increasing research interest
Individual cardiac time intervals (CTIs) success rates were evaluated in certain studies as well
Arya et al noted a significant reduction in signal acquisition between 25 to 30 weeks gestational ages (GA) [21]

Summary

Introduction

Non-invasive fetal electrocardiogram (NIFECG) is an evolving technology in fetal surveillance which is attracting increasing research interest. Evaluation of the fetal cardiac activity remains a cornerstone of obstetric practice These are broadly classified into invasive and non-invasive forms of monitoring. Direct fetal electrocardiogram (FECG) One approach to improving signal detection is the use of the fetal scalp electrode (FSE). This involves the direct application of an electrode to the fetal scalp and requires adequate cervical dilation as well as rupture of the amniotic membranes. This method provides a more reliable measurement of the FHR than indirect CTG. There is a small risk of injury to the fetal scalp and use of the FSE is relatively contraindicated in preterm infants and contraindicated in fetuses with bleedings disorders, instances of maternal viremia (such as Hepatitis B/C/D/ E as well as Human Immunodeficiency Virus) and chorioamnionitis [2, 6]

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