Evaluation of Abdominal Fetal Electrocardiography in Early Intrauterine Growth Restriction

Abstract

Objectives: This descriptive study was performed to evaluate the capability of a non-invasive transabdominal electrocardiographic system to extract clear fetal electrocardiographic (FECG) measurements from intrauterine growth restricted (IUGR) fetuses and to assess whether abdominal FECG parameters can be developed as markers for evaluating the fetal cardiac status in IUGR.Methods: Transabdominal FECG was attempted in 20 controls and 15 IUGR singleton pregnancies at 20+0−33+6 weeks gestation. Standard ECG parameters were compared between the study groups and evaluated for their correlation. Accuracy for the prediction of IUGR by cut off values of the different FECG parameters was also determined.Results: Clear P-QRST complexes were recognized in all cases. In the IUGR fetuses, the QT and QTc intervals were significantly prolonged (p = 0.017 and p = 0.002, respectively). There was no correlation between ECG parameters and Doppler or other indices to predict IUGR. The generation of cut off values for detecting IUGR showed increasing sensitivities but decreasing specificities with the prolongation of ECG parameters.Conclusion: The study of fetal electrocardiophysiology is now feasible through a non-invasive transabdominal route. This study confirms the potential of FECG as a clinical screening tool to aid diagnosis and management of fetuses after key limitations are addressed. In the case of IUGR, both QT and QTc intervals were significantly prolonged and thus validate earlier study findings where both these parameters were found to be markers of diastolic dysfunction. This research is a useful prelude to a test of accuracy and Receiver Operating Characteristics (ROC) study.

Model based estimation of QT intervals in non-invasive fetal ECG signals

“…The other records that were used for validation were DUS and fsECG. In DUS records, end of T waves is equivalent to the Ac as mentioned in several literature [2,[23][24][25][26][27]. In this study, the time duration in which an Ac point was identified between two R peaks was approximately 170 ms-330 ms from an R peak.…”

“…C. Velayo el al. [2] report fHR, QT and QTc values of (149 ± 9) bpm, (234 ± 23) ms and (370 ± 40) ms, respectively, for 20 healthy fetuses (GA: 20-33 weeks). C. Velayo el al.…”

“…In fECG, frequency is equivalent to HR, and HR is the inverse of RR interval [19]. Therefore, the time constant RC in (1), was replaced by a variable based on RR interval and the expression in (2). The model in this study calculates T-end points beat by beat, thus, RR interval was considered one beat at a time.…”

“…Many heart defects and complications start developing during the prenatal period [1,2]. It is estimated that around 1 out of 125 babies develop congenital heart defects before their birth [1].…”

“…Some of the born babies may suffer from minor heart defects that go undiagnosed for years [1]. For example, intrauterine growth restriction (IUGR), which affects around 3%-10% of pregnant women, has been associated with several cardiovascular diseases that develop during adulthood [2]. Therefore, to reduce the number of cardiovascular complications, fetal heart rate (fHR) monitoring has grown to be a vital procedure for pregnant women [3].…”