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Background: Phase-rectified signal averaging, an innovative signal processing technique, can be used to investigate quasi-periodic oscillations in noisy, nonstationary signals that are obtained from fetal heart rate. Phase-rectified signal averaging is currently the best method to predict survival after myocardial infarction in adult cardiology. Application of this method to fetal medicine has established significantly better identification than with short-term variation by computerized cardiotocography of growth-restricted fetuses., Objective: The aim of this study was to determine the longitudinal progression of phase-rectified signal averaging indices in severely growth-restricted human fetuses and the prognostic accuracy of the technique in relation to perinatal and neurologic outcome., Study Design: Raw data from cardiotocography monitoring of 279 human fetuses were obtained from 8 centers that took part in the multicenter European "TRUFFLE" trial on optimal timing of delivery in fetal growth restriction. Average acceleration and deceleration capacities were calculated by phase-rectified signal averaging to establish progression from 5 days to 1 day before delivery and were compared with short-term variation progression. The receiver operating characteristic curves of average acceleration and deceleration capacities and short-term variation were calculated and compared between techniques for short- and intermediate-term outcome., Results: Average acceleration and deceleration capacities and short-term variation showed a progressive decrease in their diagnostic indices of fetal health from the first examination 5 days before delivery to 1 day before delivery. However, this decrease was significant 3 days before delivery for average acceleration and deceleration capacities, but 2 days before delivery for short-term variation. Compared with analysis of changes in short-term variation, analysis of (delta) average acceleration and deceleration capacities better predicted values of Apgar scores <7 and antenatal death (area under the curve for prediction of antenatal death: delta average acceleration capacity, 0.62 [confidence interval, 0.19-1.0]; delta short-term variation, 0.54 [confidence interval, 0.13-0.97]; P=.006; area under the curve for prediction Apgar <7: average deceleration capacity <24 hours before delivery, 0.64 [confidence interval, 0.52-0.76]; short-term variation <24 hours before delivery, 0.53 [confidence interval, 0.40-0.65]; P=.015). Neither phase-rectified signal averaging indices nor short-term variation showed predictive power for developmental disability at 2 years of age (Bayley developmental quotient, <95 or <85)., Conclusion: The phase-rectified signal averaging method seems to be at least as good as short-term variation to monitor progressive deterioration of severely growth-restricted fetuses. Our findings suggest that for short-term outcomes such as Apgar score, phase-rectified signal averaging indices could be an even better test than short-term variation. Overall, our findings confirm the possible value of prospective trials based on phase-rectified signal averaging indices of autonomic nervous system of severely growth-restricted fetuses., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Objective: Decreased fetal heart rate variability is associated with higher perinatal morbidity and mortality in intrauterine growth restriction (IUGR). This study used a new method [phase-rectified signal averaging (PRSA)] to calculate acceleration- and deceleration-related fluctuations of the fetal heart rate., Method: Cardiotocograms from 74 growth-restricted and 161 normal fetuses were included. Both groups were matched for gestational age. The transformed PRSA signal was quantified by the acceleration-related parameter-averaged acceleration capacity (AAC) and compared to the standard short-term variation (STV). Mann-Whitney test and receiver operator characteristic (ROC) curves were used for statistical analysis., Results: For AAC, the median values of the IUGR group and control group were 1.97 bpm [interquartile range (IQR): 1.66-2.23] and 2.49 bpm (IQR: 2.24-2.72), respectively. For STV, these values were 5.44 ms (IQR: 4.49-7.38) and 7.79 ms (IQR: 6.35-9.66), respectively. The area under the ROC curve was 81.4% for AAC and 70.5% for STV., Conclusion: The results of AAC are in both groups comparable to STV. Longitudinal studies are needed to investigate the association of AAC with the clinical outcome of the newborn., (Copyright © 2011 John Wiley & Sons, Ltd.)

Objective: To identify sensitivity and specificity of computerised cardiotocography (CTG) analysis for fetal acidosis during delivery., Design: Retrospective observational study., Setting: Tertiary referral labour ward, Technical University München (TUM) and University Witten/Herdecke (UWH)., Population: All deliveries, which had at least one fetal scalp pH measurement and electronically saved CTG traces, between 2000 and 2002 (TUM) and between 2004 and 2005 (UWH)., Method: Correlation analysis of fetal scalp pH values and computerised International Federation of Obstetrics and Gynecology (FIGO) classification using 'CTG Online' program of digitally saved CTG traces., Main Outcome Measures: Fetal scalp pH values, FIGO parameter (baseline, variability, acceleration and deceleration) using computerised analysis., Results: Both collectives showed a high sensitivity (95.0%) for computerised FIGO classification 'suspect' and 'pathological', together with a low specificity (21.8%) for fetal acidosis. The most sensitive single FIGO parameter was deceleration. Very low sensitivity (<50%) was shown for the parameters variability and acceleration., Conclusions: Computerised CTG analysis is highly sensitive for fetal acidosis and can be used as an objective adjunctive criterion during delivery. Further CTG data are needed to adjust and optimise each FIGO parameter and increase sensitivity and specificity.

Objectives: This study was performed to prove, if the use of methods, that are based on procedures for analysis of chaotic systems ("complexity analysis"), can give information on the fetal condition during birth and predict both the course of delivery and fetal outcome., Patients and Methods: Fetal ECG was derived in 37 pregnancies (36-42 weeks of gestation) during birth for two to seven hours. In 12 cases delivery was uncomplicated, in 24 cases FHR tracings had been pathological., Results: Complexity analysis of fetal ECG signals showed within short observation intervals criteria that may be a hint for imminent fetal distress and acidosis., Conclusions: Application of complexity analysis in the future may give additional information for evaluation of intrapartum CTG in cases of suspicious FHR patterns.