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The effects of asymmetric volume conductor modeling on non-invasive fetal ECG extraction

journal contribution
posted on 2018-10-01, 00:00 authored by Emerson Keenan, Chandan KarmakarChandan Karmakar, Marimuthu Palaniswami
OBJECTIVE: Non-invasive fetal electrocardiography (NI-FECG) shows promise for capturing novel physiological information that may indicate signs of fetal distress. However, significant deterioration in NI-FECG signal quality occurs during the presence of a highly non-conductive layer known as vernix caseosa which forms on the fetal body surface beginning in approximately the 28th week of gestation. This work investigates asymmetric modeling of vernix caseosa and other maternal-fetal tissues in accordance with clinical observations and assesses their impacts for NI-FECG signal processing. APPROACH: We develop a process for simulating dynamic maternal-fetal abdominal ECG mixtures using a synthetic cardiac source model embedded in a finite element volume conductor. Using this process, changes in NI-FECG signal morphology are assessed in an extensive set of finite element models including spatially variable distributions of vernix caseosa. MAIN RESULTS: Our simulations show that volume conductor asymmetry can result in over 70% error in the observed T/QRS ratio and significant changes to signal morphology compared to a homogeneous volume conductor model. Volume conductor effects must be considered when analyzing T/QRS ratios obtained via NI-FECG and should be considered in future algorithm benchmarks using simulated data. SIGNIFICANCE: This work shows that without knowledge of the influence of volume conductor effects, clinical evaluation of the T/QRS ratio derived via NI-FECG should be avoided.

History

Journal

Physiological measurement

Volume

39

Issue

10

Article number

105013

Pagination

1 - 16

Publisher

IOP Publishing

Location

Bristol, Eng.

ISSN

0967-3334

eISSN

1361-6579

Language

eng

Publication classification

C Journal article; C1 Refereed article in a scholarly journal

Copyright notice

2018, Institute of Physics and Engineering in Medicine