Hyper-Chaos and Singular Beats in Congestive Heart Failure

Transient hyper-chaos with extraordinary high strength was observed in HRV of CHF patients by means of numerical titration method based on Volterra-Wiener series. In comparison with healthy subjects, RR series of CHF patients present sporadic impulses composed of normal, rather then premature beats. To illustrate such impulses and its relation to hyper-chaos, a sinoatrial node (SAN) model was developed. Simulations showed that high norepinephrine and low acetylcholine concentrations induced singularity in RR intervals and resulted in hyper-chaos. It is consistent with the high sympathetic and low parasympathetic tones in CHF.