NUOVI METODI DI ANALISI DELL'ELETTROCARDIOGRAMMA FETALE ACQUISITO PER VIA TRANS-ADDOMINALE
Tesi di Dottorato
Data di Pubblicazione:
2014
Citazione:
NUOVI METODI DI ANALISI DELL'ELETTROCARDIOGRAMMA FETALE ACQUISITO PER VIA TRANS-ADDOMINALE / T. Stampalija ; coordinatore: R. Weinstein ; tutor: E.M. Ferrazzi. DIPARTIMENTO DI SCIENZE BIOMEDICHE E CLINICHE "L. SACCO", 2014 Mar 10. 26. ciclo, Anno Accademico 2013. [10.13130/stampalija-tamara_phd2014-03-10].
Abstract:
NEW METHODS OF ANALYSIS OF TRANS-ABDOMINALLY ACQUIRED FETAL ELECTROCARDIOGRAM
Background.
Our group was one of the first to apply Phase Rectified Signal Averaging (PRSA) analysis in obstetric field by analyzing fetal ECG acquired non-invasively by trans-abdominal ECG. PRSA is a new method that emphasizes quasi-periodic oscillations masked by unrelated non-stationary elements in the signal. It is robust to the non-stationarities, noise and artifacts, and, thus, this method is superior to standard methods of heart rate (HR) evaluation such as power spectral analysis. The PRSA series can be employed to quantify the “average acceleration capacity” (AAC) and “average deceleration capacity” (ADC) of the signal. When applied to HR, AAC and ADC represent an indirect integrated quantification of the activities of the sympathetic and parasympathetic autonomic systems.
In a previous study, we explored the correlation between AAC and ADC and acid-base status in an in-vivo pregnant sheep model at term exposed to acute hypoxia (progressive umbilical cord occlusions)[Submitted for publication]. We also evaluated specific PRSA parameters (in particular the T value that determines the frequencies over which AAC and ADC are computed). In conclusion, our study showed the evidence of autonomic nervous system (ANS) activation in sheep fetus exposed to acute hypoxia through a computation of ACC and ADC of FHR, and proved a correlation with acid-base status biomarkers (T 2÷6 best enhanced differences among different grades of hypoxic severity, and the correlation between AAC/ADC and acid-base biomarkers was highest in that interval).
Based on our preliminary results we have hypothesized that AAC and ADC might reflect more closely the homeostasis of the ANS than short-term variation (STV), and thus might be used in the monitoring of the fetal wellbeing in fetuses with intrauterine growth restriction (IUGR). Indeed, IUGR fetuses are exposed to chronic nutrient deprivation and hypoxemia that can alter ANS regulation of cardio-vascular system, and, thus, affect FHR variability.
Aim of the study
The aim of the study was to investigate AAC and ADC computed by PRSA analysis on fetal ECG obtained by trans-abdominal ECG in preterm IUGR (<34 weeks) fetuses, and to explore the influence of different T values on AAC and ADC computation in relation to IUGR. Relationship of AAC and ADC with STV and Doppler velocimetry parameters of utero-placental and feto-placental districts has been also evaluated.
Material and methods
This is a prospective longitudinal single center case-control study. Preterm IUGR (<34 weeks), n=22, were recruited at admission and monitored on daily bases until delivery by trans-abdominal fetal ECG (Monica AN24, Monica Healthcare, UK). The results of fetal ECG were blinded to the management clinicians and midwifes. Computerized CTG, Doppler velocimetry evaluation of utero-placental-fetal districts, and timing of delivery were performed according to standard hospital protocol. A control group was made of uncomplicated pregnancies matched for gestational age recruited at low risk antenatal clinic (n=37).
Fetal ECG was analyzed off-line by PRSA method, and AAC and ADC were computed for T values in a range 1÷50. Differences between IUGR and healthy fetuses matched for gestational age were evaluated. In order to account for gestational age influence on ANS maturation, we divided the cohort in two sub-groups: 26-<30 weeks, and ≥30-<34 weeks, respectively. Correlation with Doppler velocimetry parameters was evaluated.
Principal findings of the study
1) In the 26-<30 weeks group, except for T=1, the AAC and ADC were significantly lower in IUGR fetuses than in matched for gestational age healthy fetuses (for T values 2÷50)
Tipologia IRIS:
Tesi di dottorato
Keywords:
fetal ECG ; PRSA ; IUGR
Elenco autori:
T. Stampalija
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