title: Computation of nonlinear parameters of heart rhythm using short time ECG segments.
abstract: We propose the method to compute the nonlinear parameters of heart rhythm (correlation dimension D₂ and correlation entropy K₂) using 5-minute ECG recordings preferred for screening of population. Conversion of RR intervals' time series into continuous function x(t) allows getting the new time series with different sampling rate dt. It has been shown that for all dt (250, 200, 125, and 100 ms) the cross-plots of D₂ and K₂ against embedding dimension m for phase-space reconstruction start to level off at m = 9. The sample size N at different sampling rates varied from 1200 at dt = 250 ms to 3000 at dt = 100 ms. Along with, the D₂ and K₂ means were not statistically different; that is, the sampling rate did not influence the results. We tested the feasibility of the method in two models: nonlinear heart rhythm dynamics in different states of autonomous nervous system and age-related characteristics of nonlinear parameters. According to the acquired data, the heart rhythm is more complex in childhood and adolescence with more influential parasympathetic influence against the background of elevated activity of sympathetic autonomous nervous system.
authors: Department of Medical Biophysics and Informatics, Karaganda State Medical University, Gogol Street 40, Karaganda 100008, Kazakhstan.
authors: Berik
authors: B
authors: Koichubekov
authors: Department of Medical Biophysics and Informatics, Karaganda State Medical University, Gogol Street 40, Karaganda 100008, Kazakhstan.
authors: Ilya
authors: I
authors: Korshukov
authors: Department of Medical Biophysics and Informatics, Karaganda State Medical University, Gogol Street 40, Karaganda 100008, Kazakhstan.
authors: Nazgul
authors: N
authors: Omarbekova
authors: Department of Medical Biophysics and Informatics, Karaganda State Medical University, Gogol Street 40, Karaganda 100008, Kazakhstan.
authors: Viktor
authors: V
authors: Riklefs
authors: Department of Medical Biophysics and Informatics, Karaganda State Medical University, Gogol Street 40, Karaganda 100008, Kazakhstan.
authors: Marina
authors: M
authors: Sorokina
authors: Department of Medical Biophysics and Informatics, Karaganda State Medical University, Gogol Street 40, Karaganda 100008, Kazakhstan.
authors: Xenia
authors: X
authors: Mkhitaryan
mesh_terms: D000293:Adolescent; D000328:Adult; D000465:Algorithms; D001341:Autonomic Nervous System; D002648:Child; D003198:Computer Simulation; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D064368:Healthy Volunteers; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D017711:Nonlinear Dynamics; D012815:Signal Processing, Computer-Assisted; D055815:Young Adult