Article

Journal of Biological Physics

, Volume 32, Issue 2, pp 117-128

Analysis of Non-stationary Data for Heart-rate Fluctuations in Terms of Drift and Diffusion Coefficients

  • F. GhasemiAffiliated withInstitute for Studies in Theoretical Physics and Mathematics
  • , Muhammad SahimiAffiliated withDepartment of Chemical Engineering, University of Southern California
  • , J. PeinkeAffiliated withCarl von Ossietzky University, Institute of Physics
  • , M. Reza Rahimi TabarAffiliated withCNRS UMR 6202, Observatoire de la Côte d’AzurDepartment of Physics, Sharif University of Technology

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Abstract

We describe a method for analyzing the stochasticity in non-stationary data for the beat-to-beat fluctuations in the heart rates of healthy subjects, as well as those with congestive heart failure. The method analyzes the return time series of the data as a Markov process, and computes the Markov time scale, i.e., the time scale over which the data are a Markov process. We also construct an effective stochastic continuum equation for the return series. We show that the drift and diffusion coefficients, as well as the amplitude of the return time series for healthy subjects are distinct from those with CHF. Thus, the method may potentially provide a diagnostic tool for distinguishing healthy subjects from those with congestive heart failure, as it can distinguish small differences between the data for the two classes of subjects in terms of well-defined and physically-motivated quantities.

Keywords

non-stationary time series heart interbeat Fokker-Planck equation drift and diffusion