Decreased chaos and increased nonlinearity of heart rate time series in patients with panic disorder

Rao, Radhakrishna KA and Yeragani, Vikram Kumar (2001) Decreased chaos and increased nonlinearity of heart rate time series in patients with panic disorder. In: Autonomic Neuroscience: Basic and Clinical, 88 (1-2). pp. 99-108.

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Abstract

In this study, we investigated measures of nonlinear dynamics and chaos of heart rate time series in 30 normal control subjects and 36 age-matched patients with panic disorder in supine and standing postures. We obtained minimum embedding dimension (MED), largest Lyapunov exponent (LLE) and measures of nonlinearity (NL) of heart rate time series. MED quantifies system's complexity, LLE predictability and NL, deviation from linear processes. There was a significant increase in complexity (p<0.00001), an increase in predictability (decreased chaos) (p<0.00001) and an increase in nonlinearity (Snet GS) (p=0.00001), especially in supine posture in patients with panic disorder. Increased NL score in supine posture may be due to a relative increase in cardiac sympathetic activity and an overall decrease in LLE may indicate an impaired cardiac autonomic flexibility in these patients due possibly to a decrease in cardiac vagal activity. These findings may further explain the reported higher incidence of cardiovascular mortality in patients with anxiety disorders

Item Type:	Journal Article
Publication:	Autonomic Neuroscience: Basic and Clinical
Publisher:	Elsevier Science
Additional Information:	Copyright of this article belongs to Elsevier Science.
Keywords:	Panic disorder;Nonlinear;Chaos;Spectral;Heart rate variability;Lyapunov exponent;Posture.
Department/Centre:	Division of Electrical Sciences > Electrical Communication Engineering
Date Deposited:	18 Mar 2009 05:37
Last Modified:	19 Sep 2010 04:53
URI:	http://eprints.iisc.ac.in/id/eprint/16808

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