Unstable periodic orbits in human cardiac rhythms

K. Narayanan, R. B. Govindan, M. S. Gopinathan

Research output: Contribution to journalArticlepeer-review

33 Scopus citations


Unstable periodic orbits (UPOs) extracted from experimental electrocardiograph signals are reported for normal and pathological human cardiac rhythms. The periodicity and distribution of the orbits on the chaotic attractor are found to be indicative of the state of health of the cardiac system. The normal cardiac system is characterized by three to four UPOs with typical periodicities and intensities. However, pathological conditions such as premature ventricular contraction, atrio ventricular block, ventricular tachy arrhythmia, and ventricular fibrillation have UPOs whose periodicity and intensity distribution are quite distinct from those of the healthy cases and are characteristic of the pathological conditions. Eigenvalues and the largest positive Lyapunov exponent value for the UPOs are also reported. The UPOs are shown to be insensitive to the embedding dimension and the present UPO analysis is demonstrated to be reliable by the method of surrogate analysis.

Original languageEnglish (US)
Pages (from-to)4594-4603
Number of pages10
JournalPhysical Review E - Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics
Issue number4
StatePublished - 1998
Externally publishedYes

ASJC Scopus subject areas

  • Statistical and Nonlinear Physics
  • Statistics and Probability
  • Condensed Matter Physics


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