# NON-LINEAR ANALYSIS OF FETAL HEART RATE IN CARDIOTOCOGRAPHY USING SAMPLE ENTROPY

### J. A. L. Marques, P. C. Cortez, J. P. V. Madeiro, F. S. Schlindwein

#### Abstract

The complex system of mother and foetus interacting during pregnancy contains both dependent and independent subsystems and it is unlikely that it can be studied using only linear techniques. Considering this, the conventional medical analysis of Fetal Heart Rate (FHR) based on Cardiotocography (CTG) traces can be expanded considering nonlinear approaches. This work presents the use of Sample Entropy (SampEn) as a measure of system complexity, using a 5 minutes window of FHR signal (1200 samples), using values for parameters m and r based on literature to analyse the signal complexity behaviour in time. The database is comprised of 22 pre-classified intrapartum exams, expected to have a high degree of time domain dynamics. The analysis shows that severe FHR decelerations result in small values of SampEn, reflecting a low level of complexity. On the other hand, a set of high level transient FHR accelerations also causes the same effect. The occurrences of repetitive patterns (similar to sinusoidal waves, which are pathological) cause a drop of SampEn values. The results encourage us to consider SampEn as one viable parameter for nonlinear FHR signal analysis.

#### References

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#### Paper Citation

#### in Harvard Style

A. L. Marques J., Cortez P., Madeiro J. and Schlindwein F. (2012). **NON-LINEAR ANALYSIS OF FETAL HEART RATE IN CARDIOTOCOGRAPHY USING SAMPLE ENTROPY** . In *Proceedings of the International Conference on Bio-inspired Systems and Signal Processing - Volume 1: BIOSIGNALS, (BIOSTEC 2012)* ISBN 978-989-8425-89-8, pages 244-248. DOI: 10.5220/0003776502440248

#### in Bibtex Style

@conference{biosignals12,

author={J. A. L. Marques and P. C. Cortez and J. P. V. Madeiro and F. S. Schlindwein},

title={NON-LINEAR ANALYSIS OF FETAL HEART RATE IN CARDIOTOCOGRAPHY USING SAMPLE ENTROPY},

booktitle={Proceedings of the International Conference on Bio-inspired Systems and Signal Processing - Volume 1: BIOSIGNALS, (BIOSTEC 2012)},

year={2012},

pages={244-248},

publisher={SciTePress},

organization={INSTICC},

doi={10.5220/0003776502440248},

isbn={978-989-8425-89-8},

}

#### in EndNote Style

TY - CONF

JO - Proceedings of the International Conference on Bio-inspired Systems and Signal Processing - Volume 1: BIOSIGNALS, (BIOSTEC 2012)

TI - NON-LINEAR ANALYSIS OF FETAL HEART RATE IN CARDIOTOCOGRAPHY USING SAMPLE ENTROPY

SN - 978-989-8425-89-8

AU - A. L. Marques J.

AU - Cortez P.

AU - Madeiro J.

AU - Schlindwein F.

PY - 2012

SP - 244

EP - 248

DO - 10.5220/0003776502440248