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. 2023 May 10;12(10):3380.
doi: 10.3390/jcm12103380.

A Small Scale Optically Pumped Fetal Magnetocardiography System

David Wurm  1 , Peter Ewert  2 , Peter Fierlinger  1 , Ronald T Wakai  3 , Verena Wallner  1 , Lena Wunderl  1 , Annette Wacker-Gußmann  2
Affiliations

A Small Scale Optically Pumped Fetal Magnetocardiography System

David Wurm et al. J Clin Med. .

Abstract

Introduction: Fetal magnetocardiography (fMCG) is considered the best technique for diagnosis of fetal arrhythmia. It is superior to more widely used methods such as fetal, fetal electrocardiography, and cardiotocography for evaluation of fetal rhythm. The combination of fMCG and fetal echocardiography can provide a more comprehensive evaluation of fetal cardiac rhythm and function than is currently possible. In this study, we demonstrate a practical fMCG system based on optically pumped magnetometers (OPMs).

Methods: Seven pregnant women with uncomplicated pregnancies underwent fMCG at 26-36 weeks' gestation. The recordings were made using an OPM-based fMCG system and a person-sized magnetic shield. The shield is much smaller than a shielded room and provides easy access with a large opening that allows the pregnant woman to lie comfortably in a prone position.

Results: The data show no significant loss of quality compared to data acquired in a shielded room. Measurements of standard cardiac time intervals yielded the following results: PR = 104 ± 6 ms, QRS = 52.6 ± 1.5 ms, and QTc = 387 ± 19 ms. These results are compatible with those from prior studies performed using superconducting quantum interference device (SQUID) fMCG systems.

Conclusions: To our knowledge, this is the first European fMCG device with OPM technology commissioned for basic research in a pediatric cardiology unit. We demonstrated a patient-friendly, comfortable, and open fMCG system. The data yielded consistent cardiac intervals, measured from time-averaged waveforms, compatible with published SQUID and OPM data. This is an important step toward making the method widely accessible.

Keywords: MSR; OPM; cardiac time intervals; fMCG; fetal arrhythmia; low cost; person-size shields.

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Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1
Figure 1
Rendering of the magnetic shielding (a) surrounding the bed (b) where the patient lies in a prone position directly above the OPM sensor support ((c) and insert). Idealized magnetic field lines are shown in red. The large opening grants easy access and continuous visual monitoring during measurements (d).
Figure 2
Figure 2
Plot of the cardiac time intervals (crosses) shown along reference data adapted from [20] (circles) and SQUID data adapted from [21] as solid lines with shaded bands spanning from the 5th to the 95th percentile.
See this image and copyright information in PMC

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