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. Ghasemi
    • Institute for Studies in Theoretical Physics and Mathematics
  • Muhammad Sahimi
    • Department of Chemical EngineeringUniversity of Southern California
  • J. Peinke
    • Carl von Ossietzky UniversityInstitute of Physics
  • M. Reza Rahimi Tabar
    • CNRS UMR 6202Observatoire de la Côte d’Azur
    • Department of PhysicsSharif University of Technology

DOI: 10.1007/s10867-006-9006-z

Cite this article as:
Ghasemi, F., Sahimi, M., Peinke, J. et al. J Biol Phys (2006) 32: 117. doi:10.1007/s10867-006-9006-z


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.


non-stationary time seriesheart interbeatFokker-Planck equationdrift and diffusion

Copyright information

© Springer Science+Business Media, Inc. 2006