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Dependency of magnetocardiographically determined fetal cardiac time intervals on gestational age, gender and postnatal biometrics in healthy pregnancies.

Van Leeuwen P, Lange S, Klein A, Geue D, Grönemeyer DH - BMC Pregnancy Childbirth (2004)

Bottom Line: Gender differences were found only for the QRS complex from the 31st week onward (p < 0.05).The influence on the P wave or QRS complex of biometric data, collected in a subgroup in whom recordings were available within 1 week of birth, did not display statistical significance.Fetal development is thus in part reflected in the CTI and may be useful in the identification of intrauterine growth retardation.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Biomagnetism, Research and Development Center for Microtherapy (EFMT), Universitätsstr, 142, 44799 Bochum, Germany. petervl@microtherapy.de

ABSTRACT
BACKGROUND: Magnetocardiography enables the precise determination of fetal cardiac time intervals (CTI) as early as the second trimester of pregnancy. It has been shown that fetal CTI change in course of gestation. The aim of this work was to investigate the dependency of fetal CTI on gestational age, gender and postnatal biometric data in a substantial sample of subjects during normal pregnancy. METHODS: A total of 230 fetal magnetocardiograms were obtained in 47 healthy fetuses between the 15th and 42nd week of gestation. In each recording, after subtraction of the maternal cardiac artifact and the identification of fetal beats, fetal PQRST courses were signal averaged. On the basis of therein detected wave onsets and ends, the following CTI were determined: P wave, PR interval, PQ interval, QRS complex, ST segment, T wave, QT and QTc interval. Using regression analysis, the dependency of the CTI were examined with respect to gestational age, gender and postnatal biometric data. RESULTS: Atrioventricular conduction and ventricular depolarization times could be determined dependably whereas the T wave was often difficult to detect. Linear and nonlinear regression analysis established strong dependency on age for the P wave and QRS complex (r2 = 0.67, p < 0.001 and r2 = 0.66, p < 0.001) as well as an identifiable trend for the PR and PQ intervals (r2 = 0.21, p < 0.001 and r2 = 0.13, p < 0.001). Gender differences were found only for the QRS complex from the 31st week onward (p < 0.05). The influence on the P wave or QRS complex of biometric data, collected in a subgroup in whom recordings were available within 1 week of birth, did not display statistical significance. CONCLUSION: We conclude that 1) from approximately the 18th week to term, fetal CTI which quantify depolarization times can be reliably determined using magnetocardiography, 2) the P wave and QRS complex duration show a high dependency on age which to a large part reflects fetal growth and 3) fetal gender plays a role in QRS complex duration in the third trimester. Fetal development is thus in part reflected in the CTI and may be useful in the identification of intrauterine growth retardation.

No MeSH data available.


Related in: MedlinePlus

Number of recordings Number of FMCG recordings obtained between the 12th and 42nd week of gestation. Viable recordings were available as early as the 15th week and, from the 20th week on, all recordings could be evaluated (no signal = signal-to-noise ratio too low for the identification of fetal QRS complexes; signal = sufficient signal quality for evaluation).
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Figure 1: Number of recordings Number of FMCG recordings obtained between the 12th and 42nd week of gestation. Viable recordings were available as early as the 15th week and, from the 20th week on, all recordings could be evaluated (no signal = signal-to-noise ratio too low for the identification of fetal QRS complexes; signal = sufficient signal quality for evaluation).

Mentions: The subjects in this study included 43 women in 47 healthy pregnancies (32 ± 3 years of age) in which fetal gender was documented. Subjects excluded from this study were those in whom the fetuses exhibited arrhythmic beats [13], IUGR, congenital heart disease or in which maternal hypertension, diabetes or nicotine abuse was present. Of the included subjects, 20 were para 0, 23 para I and 4 para II. Twenty-eight (60%) of the fetuses were male, 19 (40%) were female. We recorded 255 FMCGs between the 12th and 42nd week of gestation, of which 230 displayed sufficient signal quality to enable evaluation. All of the 25 recordings which could not be evaluated were prior to the 20th week, the success rates between the 12th and 19th week being 0%, 0%, 0%, 17%, 29%, 17%, 80% and 90% (Fig. 1). Of the remaining 230 available FMCGs between the 15th and 42nd week of gestation, we obtained on average 4.9 ± 4.3 per fetus (range 1–23). In the period from the 18th to the 39th week, the number of recordings per week of gestation lay between 6 and 14 (10.0 ± 2.3), before the 18th and after the 39th week the number of recordings was between one and three per week of gestation (Fig. 1). Of all evaluated recordings, 116 (50.4%) were performed in male fetuses, 114 (49.6%) in female. The study is in compliance with the Helsinki Declaration, was approved by the local ethics committee and all mothers gave written informed consent.


Dependency of magnetocardiographically determined fetal cardiac time intervals on gestational age, gender and postnatal biometrics in healthy pregnancies.

Van Leeuwen P, Lange S, Klein A, Geue D, Grönemeyer DH - BMC Pregnancy Childbirth (2004)

Number of recordings Number of FMCG recordings obtained between the 12th and 42nd week of gestation. Viable recordings were available as early as the 15th week and, from the 20th week on, all recordings could be evaluated (no signal = signal-to-noise ratio too low for the identification of fetal QRS complexes; signal = sufficient signal quality for evaluation).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC411040&req=5

Figure 1: Number of recordings Number of FMCG recordings obtained between the 12th and 42nd week of gestation. Viable recordings were available as early as the 15th week and, from the 20th week on, all recordings could be evaluated (no signal = signal-to-noise ratio too low for the identification of fetal QRS complexes; signal = sufficient signal quality for evaluation).
Mentions: The subjects in this study included 43 women in 47 healthy pregnancies (32 ± 3 years of age) in which fetal gender was documented. Subjects excluded from this study were those in whom the fetuses exhibited arrhythmic beats [13], IUGR, congenital heart disease or in which maternal hypertension, diabetes or nicotine abuse was present. Of the included subjects, 20 were para 0, 23 para I and 4 para II. Twenty-eight (60%) of the fetuses were male, 19 (40%) were female. We recorded 255 FMCGs between the 12th and 42nd week of gestation, of which 230 displayed sufficient signal quality to enable evaluation. All of the 25 recordings which could not be evaluated were prior to the 20th week, the success rates between the 12th and 19th week being 0%, 0%, 0%, 17%, 29%, 17%, 80% and 90% (Fig. 1). Of the remaining 230 available FMCGs between the 15th and 42nd week of gestation, we obtained on average 4.9 ± 4.3 per fetus (range 1–23). In the period from the 18th to the 39th week, the number of recordings per week of gestation lay between 6 and 14 (10.0 ± 2.3), before the 18th and after the 39th week the number of recordings was between one and three per week of gestation (Fig. 1). Of all evaluated recordings, 116 (50.4%) were performed in male fetuses, 114 (49.6%) in female. The study is in compliance with the Helsinki Declaration, was approved by the local ethics committee and all mothers gave written informed consent.

Bottom Line: Gender differences were found only for the QRS complex from the 31st week onward (p < 0.05).The influence on the P wave or QRS complex of biometric data, collected in a subgroup in whom recordings were available within 1 week of birth, did not display statistical significance.Fetal development is thus in part reflected in the CTI and may be useful in the identification of intrauterine growth retardation.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Biomagnetism, Research and Development Center for Microtherapy (EFMT), Universitätsstr, 142, 44799 Bochum, Germany. petervl@microtherapy.de

ABSTRACT
BACKGROUND: Magnetocardiography enables the precise determination of fetal cardiac time intervals (CTI) as early as the second trimester of pregnancy. It has been shown that fetal CTI change in course of gestation. The aim of this work was to investigate the dependency of fetal CTI on gestational age, gender and postnatal biometric data in a substantial sample of subjects during normal pregnancy. METHODS: A total of 230 fetal magnetocardiograms were obtained in 47 healthy fetuses between the 15th and 42nd week of gestation. In each recording, after subtraction of the maternal cardiac artifact and the identification of fetal beats, fetal PQRST courses were signal averaged. On the basis of therein detected wave onsets and ends, the following CTI were determined: P wave, PR interval, PQ interval, QRS complex, ST segment, T wave, QT and QTc interval. Using regression analysis, the dependency of the CTI were examined with respect to gestational age, gender and postnatal biometric data. RESULTS: Atrioventricular conduction and ventricular depolarization times could be determined dependably whereas the T wave was often difficult to detect. Linear and nonlinear regression analysis established strong dependency on age for the P wave and QRS complex (r2 = 0.67, p < 0.001 and r2 = 0.66, p < 0.001) as well as an identifiable trend for the PR and PQ intervals (r2 = 0.21, p < 0.001 and r2 = 0.13, p < 0.001). Gender differences were found only for the QRS complex from the 31st week onward (p < 0.05). The influence on the P wave or QRS complex of biometric data, collected in a subgroup in whom recordings were available within 1 week of birth, did not display statistical significance. CONCLUSION: We conclude that 1) from approximately the 18th week to term, fetal CTI which quantify depolarization times can be reliably determined using magnetocardiography, 2) the P wave and QRS complex duration show a high dependency on age which to a large part reflects fetal growth and 3) fetal gender plays a role in QRS complex duration in the third trimester. Fetal development is thus in part reflected in the CTI and may be useful in the identification of intrauterine growth retardation.

No MeSH data available.


Related in: MedlinePlus