Linear and nonlinear fetal heart rate analysis of normal and acidemic fetuses in the minutes preceding delivery

Gonçalves, Hernâni; Rocha, Ana Paula; Ayres-de-Campos, Diogo; Bernardes, João

doi:10.1007/s11517-006-0105-6

Cited by 96 publications

(111 citation statements)

References 33 publications

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“…With continued agonizing anoxia, linear indices decreased, whereas entropy remained stably low, denoting an overall decrease of the activity of all HR dynamics regulatory centres (Gonçalves et al 2006a, Moraru et al 2004, Beckers et al 2006b. All this evidence is consistent with human foetal studies performed in the final minutes of labour (Gonçalves et al 2006b, Siira et al 2005, as well as with non-human foetal studies developed during episodes of acute hypoxia or anoxia (Li et al 2004, Chaffin et al 1998.…”

Section: Discussionsupporting

confidence: 77%

“…Some of those indices, previously used by some of us in FHR analysis (Vieira et al 2004, Felgueiras et al 1998, may be useful, as the scaling behaviour of HR seems to be selectively related to the alpha-adrenergic activity whereas entropy appears to be related to cholinergic activity (Beckers et al 2006b). Those indices were outside the scope of this study, which was designed, like our last series of studies on FHR (Gonçalves et al 2006a(Gonçalves et al , 2006b(Gonçalves et al , 2007, to be more comparable with other FHR studies published in the literature (Magenes et al 2000, Signorini et al 2003. On the other hand, in this study an evaluation of entropy was performed in more depth than in other studies.…”

Section: Discussionmentioning

confidence: 88%

“…In this study, linear and nonlinear HR analysis during episodes of acute anoxia in adult rats was assessed. This had to do with our particular interest in HR analysis during acute anoxia, such as that occurring in the foetus during difficult labours , Gonçalves et al 2006b. Other studies have been performed before on linear and nonlinear HR analysis of acute induced anoxia in rats, but they concentrated on the evaluation of HR recovery after acute anoxia rather than on acute anoxia itself (Moraru et al 2004(Moraru et al , 2005.…”

Section: Discussionmentioning

confidence: 99%

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The Obestatin/Ghrelin System as a Novel Regulatory Mechanism of Iris Muscle Contraction

Rocha‐Sousa

Falcão‐Reis

Leite‐Moreira

2008

Current Eye Research

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The objective of this study was the assessment of heart-rate (HR) dynamics with linear and nonlinear methods during episodes of mechanical ventilation and acute anoxia in rats. Namely, to assess whether linear and nonlinear HR analysis was able to discriminate acute anoxia from baseline in rats and if this was consistent with human foetal and adult studies. Five HR segments of 1 min duration, during baseline recording, mechanical ventilation and first, second and third minutes of induced acute anoxia, were analysed in ten adult Wistar rats. Linear time and frequency domain and nonlinear methods were used, namely mean HR (mHR), long-term irregularity (LTI), interval index (II), low frequency (LF) and high frequency (HF), approximate entropy (ApEn) and sample entropy (SampEn). New parameters for the entropy indices are proposed for the analysis of rats' HR. Bootstrap percentile confidence intervals and nonparametric statistical tests were used in the evaluation of the differences between segments. During mechanical ventilation a clear spectral band was detectable at the ventilation rate, but mHR, II and the 'new' entropy indices were the only significantly changed indices. In the transition from baseline-mechanical-ventilation to mechanical-ventilationinduced anoxia, a statistically significant decrease of mHR, II and entropy indices was observed, clearly discriminating these two instances, whereas most linear indices increased. With continued anoxia, most linear indices decreased significantly, whereas entropy remained stably low. These results are consistent with other foetal human and non-human studies and evidence that the rat model may be used for further research on linear and nonlinear analysis of heart-rate dynamics. The transition from baseline to acute anoxia was encompassed by signs of increased activation of the autonomic nervous system sympathetic branch, and decreased or blunted activity of the HR complexity regulatory centres.

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Section: Discussionsupporting

confidence: 77%

Section: Discussionmentioning

confidence: 88%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

The Obestatin/Ghrelin System as a Novel Regulatory Mechanism of Iris Muscle Contraction

Rocha‐Sousa

Falcão‐Reis

Leite‐Moreira

2008

Current Eye Research

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“…MSE analysis by means of approximate entropy (ApEn) and sample entropy (SampEn), Lempel Ziv complexity analysis, PSD estimation and usual spectral indexes, but also, a multiparametric k-means cluster-based analysis have been tested on real CTGs in order to distinguish between healthy from severe and not severe IUGRs, with the multiparametric approach performing better in clinical applications. Finally, two comparison studies, the first one, between SampEn and ApEn techniques for MSE analysis in order to identify distressed foetuses and, the second one, between linear and non linear indexes in the final 20 minutes preceding the delivery to distinguish normal from acidemic foetuses are reported in [54] and [55], respectively. Support vector machines (SVMs) have been utilised in [56] for identifying FHR signals from CTG recordings likely to develop metabolic acidosis.…”

Section: Various Approachesmentioning

confidence: 99%

Survey on Cardiotocography Feature Extraction Algorithms for Foetal Welfare Assessment

Haritopoulos

Illanes

Nandi

2016

XIV Mediterranean Conference on Medical and Biological Engineering and Computing 2016

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Abstract-Since its inception forty years ago as a way to control birth process, the cardiotocograph (CTG) has emerged over time and became the undisputed leader worldwide of noninvasive intrapartum foetal monitoring systems. The CTG signals conveying a lot of information, it is very difficult to interpret them and act accordingly even for specialists; hence, researchers have started looking for characteristics which could be correlated with a particular pathological state of the foetus. Thereby, many features appeared in the literature, ranging from the most common ones to artificially generated features, and computed using a wide variety of signal processing-based analysis tools: time scale, spectral or non-linear analysis, to name but a few. This survey paper, presents in a hierarchical order the most common processing steps of a CTG signal and focuses primarily on the feature extraction methods for foetal heart rate (FHR) analysis reported in the literature during the last decade. Also, some feature classification methods are reported before a brief discussion which concludes this work.

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“…ApEn [34,36] has been widely applied in both human [17,18,23,40] and animal studies [19,20,32]. Nevertheless, the selection of ApEn parameters may significantly influence the analysis between normal and heart failure human groups [29].…”

Section: Introductionmentioning

confidence: 99%

Comparison of different methods of heart rate entropy analysis during acute anoxia superimposed on a chronic rat model of pulmonary hypertension

Gonçalves

Henriques‐Coelho

Rocha

et al. 2013

Medical Engineering & Physics

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a b s t r a c tAcute life-threatening situations are particularly critical when superimposed on chronic diseases. The objective of this study was the assessment of heart rate (HR) dynamics during episodes of acute anoxia superimposed on a rat model of chronic pulmonary hypertension. In 10 adult Wistar rats, five weeks after pulmonary hypertension induction with Monocrotaline, we analysed eight 1-min HR segments, during episodes of baseline, mechanical ventilation and acute anoxia, using linear indices, approximate entropy (ApEn), sample entropy (SampEn) and multiscale entropy (MSE). The transition from baseline or mechanical ventilation to early anoxia was identified through almost all indices, but SampEn(2,0.6) was the index that better identified all the transitions. MSE presented limited performance, possibly due to the non-stationary nature and short duration of the acute anoxia episodes. A systematic evaluation of all computed HR indices may help to identify which indices or combination of indices more adequately discriminates and monitors critical acute events superimposed on chronic clinical conditions.

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Linear and nonlinear fetal heart rate analysis of normal and acidemic fetuses in the minutes preceding delivery

Cited by 96 publications

References 33 publications

The Obestatin/Ghrelin System as a Novel Regulatory Mechanism of Iris Muscle Contraction

The Obestatin/Ghrelin System as a Novel Regulatory Mechanism of Iris Muscle Contraction

Survey on Cardiotocography Feature Extraction Algorithms for Foetal Welfare Assessment

Comparison of different methods of heart rate entropy analysis during acute anoxia superimposed on a chronic rat model of pulmonary hypertension

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