The electrical heart axis and ST events in fetal monitoring: A post-hoc analysis following a multicentre randomised controlled trial

Vullings, Rik; Verdurmen, K.M.J.; Hulsenboom, Alexandra D.J.; Scheffer, Stéphanie E.C.M.G.; Lau, Hinke de; Kwee, Anneke; Wijn, Pff Pieter; Amer‐Wåhlin, Isis; Laar, Judith O E H van; Oei, S.G.

doi:10.1371/journal.pone.0175823

Cited by 11 publications

(12 citation statements)

References 31 publications

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“…Fetuses in cephalic, transverse, or breech position would give different ECG morphology. We have shown in a previous study ( 31 ) that a different fetal orientation, or a different orientation of the electrical heart axis with respect to the abdominal electrodes, affects the degree of ST elevation and as such might affect ST alarms triggered on an obstetrical ward. Normalization for the fetal orientation would be possible by using ultrasound imaging ( 30 ) or different (i.e., relative) ST alarm mechanisms ( 32 ).…”

Section: Discussionmentioning

confidence: 96%

Non-invasive Fetal Electrocardiography for Intrapartum Cardiotocography

Vullings

Laar

2020

Front. Pediatr.

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Fetal monitoring is important to diagnose complications that can occur during pregnancy. If detected timely, these complications might be resolved before they lead to irreversible damage. Current fetal monitoring mainly relies on cardiotocography, the simultaneous registration of fetal heart rate and uterine activity. Unfortunately, the technology to obtain the cardiotocogram has limitations. In current clinical practice the fetal heart rate is obtained via either an invasive scalp electrode, that poses risks and can only be applied during labor and after rupture of the fetal membranes, or via non-invasive Doppler ultrasound technology that is inaccurate and suffers from loss of signal, in particular in women with high body mass, during motion, or in preterm pregnancies. In this study, transabdominal electrophysiological measurements are exploited to provide fetal heart rate non-invasively and in a more reliable manner than Doppler ultrasound. The performance of the fetal heart rate detection is determined by comparing the fetal heart rate to that obtained with an invasive scalp electrode during intrapartum monitoring. The performance is gauged by comparing it to performances mentioned in literature on Doppler ultrasound and on two commercially-available devices that are also based on transabdominal fetal electrocardiography.

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Section: Discussionmentioning

confidence: 96%

Non-invasive Fetal Electrocardiography for Intrapartum Cardiotocography

Vullings

Laar

2020

Front. Pediatr.

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“…The relation between the orientation of the electrical heart axis and the orientation of the scalp electrode yields different T/QRS baseline values, due to differences in ECG morphology. We found that fetuses with a higher T/QRS baseline are more prone to ST events, independent of the fetal condition [ 22 ]. In contrast, we found that fetuses with a lower T/QRS baseline are less prone to exceed the threshold for a ST event.…”

Section: Introductionmentioning

confidence: 99%

Relative versus absolute rises in T/QRS ratio by ST analysis of fetal electrocardiograms in labour: A case-control pilot study

et al. 2019

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IntroductionThe additional value of ST analysis during labour is uncertain. In ST analysis, a T/QRS baseline value is calculated from the fetal electrocardiogram and successive T/QRS ratios are compared to this baseline. However, variation in the orientation of the electrical heart axis between fetuses may yield different T/QRS baseline values. In case of a higher T/QRS baseline value more ST events are encountered, although not always related to perinatal outcome. We hypothesised that we can partly correct for this effect by analysing T/QRS rises as a percentage from baseline (relative ST analysis). This study aimed to explore whether relative ST analysis has better diagnostic value for cord acidaemia compared to conventional ST analysis, where predefined fixed T/QRS ratios are used.Methods and materialsA case-control study was performed in 20 term human fetuses during labour; 10 cases (umbilical cord artery pH <7.05 at birth, defining acidaemia) and 10 controls (pH >7.20) were included. The fetal electrocardiogram was recorded using a STAN monitor. We electronically extracted all T/QRS values, baseline and episodic ST events from the STAN monitor and calculated the relative T/QRS changes. The cut-off for relative ST events was determined in a receiver operator characteristic (ROC) curve at optimal specificity for cord acidaemia. Parameters of interest were area under the curve (AUC) of the ROC curve for relative ST events and test performance of both conventional and relative ST analysis.ResultsRelative ST analysis showed an AUC of 0.99. The optimal cut-off value for relative T/QRS rise was determined at 0.70. Relative vs conventional (absolute) ST analysis showed a specificity of 100% vs 40% (p = 0.031); sensitivity 90% vs 90%; positive likelihood ratio infinity vs 1.5; negative likelihood ratio 0.10 vs 0.25, respectively.ConclusionRelative ST analysis seems to be a promising method to detect impending fetal acidaemia during labour. Further studies are required to determine the diagnostic accuracy.

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“…Previous research has shown that variation in the orientation of the electrical heart axis between foetuses causes different T/QRS baseline values. Foetuses with a higher T/QRS baseline value were shown to be more prone to false positive ST events [26,27]. Multi-lead NI-fECG recordings can deliver a 12-lead foetal ECG, taking information on the orientation of the electrical heart axis, derived from ultrasound evaluation, into account.…”

Section: Discussionmentioning

confidence: 99%

Feasibility of non-invasive Foetal electrocardiography in a twin pregnancy

Noben

Westerhuis

Laar

et al. 2020

BMC Pregnancy Childbirth

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Background: Twin pregnancy is associated with increased perinatal mortality. Close foetal monitoring is therefore warranted. Doppler Ultrasound cardiotocography is currently the only available method to monitor both individual foetuses. Unfortunately, the performance measures of this method are poor and erroneous monitoring of the same twin with both transducers may occur, leaving the second twin unmonitored. In this study we aimed to determine the feasibility of monitoring both foetuses simultaneously in twin gestation by means of non-invasive foetal electrocardiography (NI-fECG), using an electrode patch on the maternal abdomen. Methods: A NI-fECG recording was performed at 25 + 3 weeks of gestation on a multiparous woman pregnant with dichorionic diamniotic twins. An electrode patch consisting of eight adhesive electrodes was applied on the maternal abdomen, yielding six channels of bipolar electrophysiological measurements. The output was digitized and stored for offline processing. The recorded signals were preprocessed by suppression of high-frequency noise, baseline wander, and powerline interference. Secondly, the maternal ECG was subtracted and segmentation into individual ECG complexes was performed. Finally, ensemble averaging of these individual ECG complexes was performed to suppress interferences. Results: Six different recordings were obtained from each of the six recording channels. Depending on the orientation and distance of the fetal heart with respect to each electrode, a distinction could be made between each fetus based on the morphology of the signals. Yielding of the fetal ECGs was performed manually based on the QRS complexes of each fetus. Conclusion: NI-fECG with multiple electrodes allows for monitoring of the fetal heart rate and ECG of both individual fetuses in twin pregnancies.

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The electrical heart axis and ST events in fetal monitoring: A post-hoc analysis following a multicentre randomised controlled trial

Cited by 11 publications

References 31 publications

Non-invasive Fetal Electrocardiography for Intrapartum Cardiotocography

Non-invasive Fetal Electrocardiography for Intrapartum Cardiotocography

Relative versus absolute rises in T/QRS ratio by ST analysis of fetal electrocardiograms in labour: A case-control pilot study

Feasibility of non-invasive Foetal electrocardiography in a twin pregnancy

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