effects of various degrees of coronary stenosis on Lyapunov exponents of ECG and R-R interval time series / 中国医学物理学杂志

ABSTRACT

Purpose:It has been shown that the heart is a chaotic oscillator. So it is appropriiate to use the Lyapunov exponent, an important parameter to identify the nature of non-linear dynamical systems, for identifying the state of human heart. Methods:Preliminary results are obtained in this paper using Wolf's algorithm for 8 normal and 107 abnormal ECG recordings. Results:Significant differences are found between the Lyapunov exponents of normal ECG and ECG with obvious coronary stenosis (OCS), but there is no significant difference between the Lyapunov exponents of normal ECG and ECG with mild coronary stenosis (MCS);Significant differences are also found between the Lyapunov exponents of R-R interval series of normal ECG、ECG with MCS and ECG with OCS. Conclusions:It is apparent that the R-R interval series can give us more messages about human heart, and the Lyapunov exponents of ECG and R-R interval series are the appropriate parameters for the identification of the physiological states of human heart. It is possible to use Lyapunov exponent for early diagnosis of Coronary Heart Disease.