Fetal magnetocardiography: development of the fetal cardiac time intervals

Kähler, C.; Schleußner, E; Grimm, Barbara; Schneider, A.; Schneider, Uwe; Nowak, H.; Seewald, Hans-Joachim

doi:10.1002/pd.322

Cited by 40 publications

(22 citation statements)

References 24 publications

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“…The best detection rates prior to this study were reported by K ä hler et al [14] , who also had a 100 % detection rate for QRS and P waves starting at 19 weeks GA. T wave was lowest in early GAs below 24 weeks and increased up to 100 % with a mean for all ages of 93 % (Table 3). With the fi rst dedicated fetal MEG device, it was also possible to detect QRS in 100 % of the cases; however, P wave and T wave detection increased with GA to 95.1 % and 87.3 % , respectively, but detection rates prior to 20 weeks of GA remained challenging [18] .…”

Section: Discussionsupporting

confidence: 52%

“…Moreover, the data match the fi ndings from two existing MCG multicenter studies with the largest MCG data pool. More variation was found compared to the CTIs reported in the literature [13,14,21] . Longer durations were seen in the study by Comani et al [5] .…”

Section: Discussionmentioning

confidence: 60%

“…For example, the number of channels and signal averages strongly affects the CTI estimation, as our comparison of channel selections revealed and therefore was standardized. The fewest channels and the lowest number of signal averages were found in the studies by Horigome, K ä hler, Quinn and colleagues [13,14,21] . This can explain the shorter CTIs.…”

Section: Discussionmentioning

confidence: 85%

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Fetal magnetocardiography (fMCG): moving forward in the establishment of clinical reference data by advanced biomagnetic instrumentation and analysis

Kiefer-Schmidt¹,

Lim²,

Wacker-Gußmann³

et al. 2012

Journal of Perinatal Medicine

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Cardiotocography and echocardiography are currently standard for fetal heart monitoring. However, both do not provide adequate temporal resolution to measure fetal cardiac time intervals and detect arrhythmias, which can occur during normal sinus rhythm. Fetal magnetocardiography (fMCG) is a non-invasive technique measuring magnetic signals generated by fetal heart activity. Most fMCG devices are installed in research institutions limiting the implementation of this method in a clinical setting. Several institutions made a step forward by installing devices, in particular for fetal investigations, in hospital sites to evaluate the clinical benefit. Based on instrumentation differences which can affect signal quality, there is still no established reference database for fetal cardiac time intervals. A new magnetograph dedicated to fetal recordings was implemented with improved patient comfort. The setting was optimized to establish a standard. A total of 103 healthy fetuses starting as early as possible after the first trimester were recorded and fMCG values of cardiac time intervals were compared to former studies. Data allowed high and reliable detection for all fMCG components starting at 17 weeks. The data were comparable to fMCG multicenter studies, fetal electrocardiography and neonatal ECG results and could serve as a database of norm values for further investigation of fetal arrhythmias.

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Section: Discussionsupporting

confidence: 52%

Section: Discussionmentioning

confidence: 60%

Section: Discussionmentioning

confidence: 85%

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Fetal magnetocardiography (fMCG): moving forward in the establishment of clinical reference data by advanced biomagnetic instrumentation and analysis

Kiefer-Schmidt¹,

Lim²,

Wacker-Gußmann³

et al. 2012

Journal of Perinatal Medicine

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“…However, some controversy exists on this point. Some reports showed that PR intervals are independent of gestational age [9,19,20]. …”

Section: Discussionmentioning

confidence: 99%

Comparison of PR Intervals Determined by Fetal Magnetocardiography and Pulsed Doppler Echocardiography

et al. 2012

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Objective: In clinical practice, measurement of mechanical PR interval (mPR) with pulsed Doppler echocardiography is a standard method used to estimate the atrioventricular conduction time in the fetus. However, fetal echocardiography does not directly reflect the electrical properties of the heart. Technological advances in fetal magnetocardiography (fMCG) have allowed recording of the electrical PR interval (ePR) with high time resolution. The aim of this study was to clarify the differences between ePR and mPR. Methods: The study subjects were 295 normal human fetuses (gestational age, range 20.4–41.4 weeks) who underwent fMCG, and 135 of them underwent fetal echocardiography 15–90 min before or after fMCG. The ePR was measured using the fMCG, and the mPR was determined by two pulsed Doppler methods, simultaneous recording of the left ventricular inward and outward flow (LV in/out) (n = 135) and superior vena cava and ascending aorta (SVC/aAo) (n = 84). Results: The ePR showed a significant, but weak, positive correlation with gestational age (r = 0.162, p = 0.0053). The mPR was significantly longer than the ePR (p < 0.0001), with mean differences of 14.6% (95% limits of agreement –10.7, 39.9) for the LV in/out method and 14.7% (95% limits of agreement –8.6, 38.0) for the SVC/aAo method. Conclusion: Our results point to the risk of overestimation of the atrioventricular conduction time when the mPR is used, and the need for careful interpretation of PR prolongation determined by mPR.

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“…At this stage, longer QT and corrected QT intervals were reported in fetal magnetocardiography and noninvasive fetal electrocardiography (14,15). More importantly, the rate of sudden death is higher in the uterus than at most other times in the human life cycle.…”

mentioning

confidence: 91%

Progesterone Impairs Human Ether-a-go-go-related Gene (HERG) Trafficking by Disruption of Intracellular Cholesterol Homeostasis

Soong

et al. 2011

Journal of Biological Chemistry

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The prolongation of QT intervals in both mothers and fetuses during the later period of pregnancy implies that higher levels of progesterone may regulate the function of the human ether-ago-go-related gene (HERG) potassium channel, a key ion channel responsible for controlling the length of QT intervals. Here, we studied the effect of progesterone on the expression, trafficking, and function of HERG channels and the underlying mechanism. Treatment with progesterone for 24 h decreased the abundance of the fully glycosylated form of the HERG channel in rat neonatal cardiac myocytes and HERG-HEK293 cells, a cell line stably expressing HERG channels. Progesterone also concentration-dependently decreased HERG current density, but had no effect on voltage-gated L-type Ca Progesterone (P4) 2 is an important steroid hormone involved in the female menstrual cycle, pregnancy, and embryogenesis. In the normal menstrual cycle, P4 levels increase from 0.6 -4.5 nmol/liter during the preovulatory phase to 10.5-80 nmol/liter during the luteal phase (1). It was reported that P4 at Ͻ100 nmol/liter, which is comparable with that occurring during the luteal phase, had no significant effect on the QT interval (2-4). However, recent studies show that P4 may shorten the action potential duration or QT interval (5). This is probably because P4 at this level enhances the rapid component of the delayed rectifier K ϩ current and inhibits L-type Ca 2ϩ currents (6). If pregnancy occurs, P4 levels are initially maintained at the luteal level, but may increase to 1 mol/liter at term (7). Elevated levels of P4 are important for the implantation of the embryo and the maintenance of a conducive environment for the embryo. At such a high level, the corrected QT interval is significantly prolonged (8, 9). This explains why pregnant women are more susceptible to ventricular arrhythmias during pregnancy, labor, and delivery (10 -12). However, it is interesting to note that in the patients with inherited long QT syndrome (LQTS) the risk for cardiac events is not higher during pregnancy than during other periods in life (10, 13). These findings suggest that the mechanisms for pregnancy-induced cardiac events in normal healthy women are different from those in the patients with inherited LQTS.In the fetus, the P4 level was reported to be very high (ϳ4.5 mol/liter) in umbilical cord vein during late stages of pregnancy (7). At this stage, longer QT and corrected QT intervals were reported in fetal magnetocardiography and noninvasive fetal electrocardiography (14, 15). More importantly, the rate of sudden death is higher in the uterus than at most other times in the human life cycle. Although the major reasons remain unknown, several studies of newborns suggest that QT prolongation and the increased risk of ventricular arrhythmias may account for the significant mortality (16,17). This may be the same for stillbirth as several case reports indicate that LQTS is one cause for otherwise unexplained fetal demise (18).The human ether-a-go-go-related gene (HE...

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Fetal magnetocardiography: development of the fetal cardiac time intervals

Abstract: FMCG provides sufficient information about all parts of the fetal cardiac conduction system from the 19th gestational week on. It offers the possibility to analyse the shape and the duration of the PQRST-complex.

Cited by 40 publications

References 24 publications

Fetal magnetocardiography (fMCG): moving forward in the establishment of clinical reference data by advanced biomagnetic instrumentation and analysis

Fetal magnetocardiography (fMCG): moving forward in the establishment of clinical reference data by advanced biomagnetic instrumentation and analysis

Comparison of PR Intervals Determined by Fetal Magnetocardiography and Pulsed Doppler Echocardiography

Progesterone Impairs Human Ether-a-go-go-related Gene (HERG) Trafficking by Disruption of Intracellular Cholesterol Homeostasis

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