Babloyantz A, Destexhe A
Faculté des Sciences, Université Libre de Bruxelles, Belgium.
Biol Cybern. 1988;58(3):203-11. doi: 10.1007/BF00364139.
With the help of several independent methods of nonlinear dynamics, the electrocardiograms (ECG) of four normal human hearts are studied qualitatively and quantitatively. A total of 36 leads were tested. The power spectrum, the autocorrelation function, the phase portrait, the Poincaré section, the correlation dimension, the Lyapunov exponent and the Kolmogorov entropy all point to the fact that the normal heart is not a perfect oscillator. The cardiac activity stems from deterministic dynamics of chaotic nature characterized by correlation dimensions D2 ranging from 3.6 to 5.2. Two different phase spaces are constructed for the evaluation of D2: the introduction of time lags and the direct use of space vectors give similar results. It is shown that the variabilities in interbeat intervals are not random but exhibit short range correlations governed by deterministic laws. These correlations may be related to the accelerating and decelerating physiological processes. This new approach to the cardiac activity may be used in clinical diagnosis. Also they are valuable tools for the evaluation of mathematical models which describe cardiac activity in terms of evolution equations.
借助几种非线性动力学的独立方法，对四颗正常人类心脏的心电图（ECG）进行了定性和定量研究。共测试了36导联。功率谱、自相关函数、相图、庞加莱截面、关联维数、李雅普诺夫指数和柯尔莫哥洛夫熵均表明，正常心脏并非完美的振荡器。心脏活动源于具有混沌性质的确定性动力学，其关联维数D2在3.6至5.2之间。为评估D2构建了两个不同的相空间：引入时间滞后和直接使用空间向量给出了相似的结果。结果表明，心跳间期的变异性并非随机的，而是呈现出由确定性规律支配的短程相关性。这些相关性可能与加速和减速的生理过程有关。这种研究心脏活动的新方法可用于临床诊断。它们也是评估用演化方程描述心脏活动的数学模型的有价值工具。
