Identification of the deterministic chaos in cardiovascular dynamics by the use of the non-linear mathematics.

Abstract

Chaotic behavior in cardiovascular dynamics was thought to be one of the important information to analyze the circulatory regulatory system. Several investigators studied the attractor in the signals of the electrocardiogram, and found the strange attractor, suggesting dynamics compatible with deterministic chaos, by the use of the non-linear mathematics. It is interesting problem to analyze the hemodynamic parameters by the use of non-linear mathematics for the determination of the physiologically optimal circulatory condition. In this study, Chaos analyzing system was developed to identify the deterministic chaos in cardiovascular regulatory system by the use of the non-linear mathematics including phase plane plots, embedding, and lyapunov exponents. Time series data of the hemodynamic parameters in the chronic animal experiments was analyzed by this system, and satisfactory attractor was obtained by the use of the phase plane plots and embedding techniques. Furthermore, calculation of the lyapunov exponents showed the existence of the deterministic chaos in arterial blood pressure in the chronic animal experiments using adult goats, suggesting this tool is useful for analyzing cardiovascular dynamic behavior.