Fetal Heart Rate Monitoring Using Maternal Abdominal Surface Electrodes in Third Trimester: Can We Obtain Additional Information Other than CTG Trace?

Abstract

Cardiotocography (CTG) is the most widely used method of monitoring fetal heart rate despite its low specificity for fetal acidosis and poor perinatal outcome [1]. It is derived from simple auscultation of the fetal heart, but currently Doppler ultrasound CTG is used for monitoring. Fetal electrocardiography has a greater potential for detecting impairment of fetal circulation; however, it is technically more difficult to perform than CTG.Methods of monitoring fetal well-being, both in the antepartum period and during labor, are constantly developed as they assist in identifying fetal hypoxia and reducing perinatal mortality and morbidity. From the first attempts of monitoring fetal heart rate and registering electrical activity of the fetal heart, researchers sought out a precise description of intrauterine fetal condition and an accurate assessment of the risk of fetal hypoxia. AbstractBackground. Cardiotocography (CTG) is the most widely used procedure despite its low specificity for fetal acidosis and poor perinatal outcome. Fetal electrocardiography (fECG) with transabdominal electrodes is a new, non--invasive and promising method with greater potential for detecting impairment of fetal circulation. This study is the first that attempts to assess the usefulness of fECG in comparison to CTG during antepartum period. Objectives. To determine if a single fECG examination along with CTG tracing and Doppler flow measurement in the fetal vessels has any additional clinical value in normal and intrauterine growth restricted (IUGR) fetuses. Material and Methods. The study included 93 pregnancies with IUGR, 37 pregnancies with IUGR and brain sparing effect, and 324 healthy pregnant women. The T/QRS ratio, cerebro-placental ratio (CRP), and CTG tracings were analyzed. One-way analysis of variance and Spearman's rank correlation coefficient were applied. The relationship between results of the T/QRS ratio and CTG examination among the study groups was analyzed. Results. The highest average mean value of the T/QRS ratio was recorded in the IUGR group with a normal CPR and a pathologic CTG (0.235 ± 0.014). The highest average maximum values were observed in the groups of IUGR pregnancies with a reduced CPR with normal (0.309 ± 0.100), suspicious (0.330 ± 0.102) and pathologic (0.319 ± 0.056) CTGs. Analysis of variance revealed differences between study groups regarding maximum values and the difference between maximum and minimal values of T/QRS. Correlations between groups were insignificant. Conclusions. Higher values of T/QRS ratio in IUGR pregnancies with normal and reduced CPR than in control group regardless of the result of CTG examination may indicate minimal worsening of intrauterine fetal well-being in growth retarded fetuses. No relationship between fECG examination and CTG tracings suggests that a single fECG does not provide any additional clinically significant information determining the condition of the fetus; however, further studies are required (Adv Clin Exp Med 2016, 25, 2, 309-316).

Non-Adaptive Methods for Fetal ECG Signal Processing: A Review and Appraisal

“… Accurate—these methods allow accurate detection of fHR, i.e., Se ≤ 85%, PPV ≤ 95%, ACC ≤ 85%, F1 ≤ 90%. Very Accurate—these methods enable a very accurate determination of fHR and, in this case, it is a full replacement of the conventional CTG [ 31 , 40 , 119 ], i.e., Se ≤ 95%, PPV ≤ 95%, ACC ≤ 95%, F1 ≤ 95%. Morphological analysis (T/QRS; QT)—this parameter classifies the efficacy of the investigated methods from a deeper morphological analysis of fECG.…”

Non-Invasive Fetal Monitoring: A Maternal Surface ECG Electrode Placement-Based Novel Approach for Optimization of Adaptive Filter Control Parameters Using the LMS and RLS Algorithms

“…This information corresponds to the visualization of the STanalysis by the Noeventa Medical ST analyzer (STAN S34). Please note that T/QRS [100,101] is calculated for 30 samples (for more information about T/QRS determination, please see [102,103]). The physiological $f\mathrm{HR}$ is relatively constant and fluctuates around the value of 140 bpm and the value of T/QRS oscillates around the value of 0.1.…”

Electrocardiography of the fetus as an optimal way to evaluate its condition

“…Под стрессовым тестом понимают реакцию сердцебиений плода на маточные сокращения, вызванные внутривенным введением матери раствора окситоцина. Была продемонстрирована связь между благопо-лучным исходом родов и наличием ответа ЧСС плода (в виде учащения ритма и увеличения его вариабельности) на двигательную активность [14]. Наряду с двигательной активностью наличие дыхательной активности также является надежным показателем благополучия плода.…”

“…Основные места установки электродов приведены в работах разных исследователей [14,15,25]. Считают, что для достоверной идентификации электрокардиосигналов плода следует стремиться к тому, чтобы электроды строго располагались над областями головки и ягодиц плода.…”

“…Сигналы ЭКГ матери наслаиваются на сигналы плода, что значительно затрудняет автоматическую обработку ЭКГ плода [6,18,22,23]. Таким образом, регистрация ЭКГ плода является достаточно сложной операцией, требующей специальных методов выделения электрокардиографического сигнала [13,14,17,20,22,24]. Однако метод ЭКГ обладает и одним неоспоримым преимуществом -он позволяет точно определять момент начала комплекса QRS плода, а следовательно, получать значительно более точную (по сравнению с другими методами регистрации) информацию о длительности кардиоцикла плода.…”