Phys Rev Lett. 2001 Aug 6;87(6):068104. Epub 2001 Jul 24. 

Noise effects on the complex patterns of abnormal heartbeats.

Schulte-Frohlinde V, Ashkenazy Y, Ivanov PC, Glass L, Goldberger AL, Stanley HE.

Center for Polymer Studies, Department of Physics, Boston University, Boston,
Massachusetts 02215, USA.

Patients at high risk for sudden death often exhibit complex heart rhythms in
which abnormal heartbeats are interspersed with normal heartbeats. We analyze
such a complex rhythm in a single patient over a 12-h period and show that the
rhythm can be described by a theoretical model consisting of two interacting
oscillators with stochastic elements. By varying the magnitude of the noise, we
show that for an intermediate level of noise, the model gives best agreement
with key statistical features of the dynamics.

PMID: 11497867 [PubMed - indexed for MEDLINE]