最近也在解這些, 來跟 hexam 兄請益 1 番

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[From: e2@] - Tue Sep 18 19:52:32 2007

http://herkules.oulu.fi/isbn9514272005/html/x244.html

回應lei兄的提問:

2.4. Non-linear analysis of heart rate dynamics

Many recent studies have shown that non-linear phenomena are involved in the genesis of HR dynamics (Sayers 1973, Goldberger & West 1987, Goldberger 1996). It has been suggested that healthy heart beat is chaotic and shows a fractal form, which may be changed upon aging and by disease (Lipsitz & Goldberger 1992, Goldberger 1996). Many authors have shown that the traditional measures of HR variability reflecting the periodic behavior of heart rate are unable to detect subtle changes in heart rate dynamics. Therefore, new methods based on the chaos theory and the fractal behavior of heart rate fluctuations have been developed to assess the random or chaotic behavior of heart rate dynamics. These non-linear measures of HR dynamics are even better predictors of mortality in selected patient populations (Huikuri et al. 1998, M&ampauml;kikallio et al. 1999b, Huikuri et al. 2000) compared to the traditional measures of HR variability.


非線性的心跳狀態是一種混亂而不規則的形式，可能是因為老化或者是疾病所引起
這樣的非線性心跳動力學在特定的族群中甚至比HRV更能預測死亡率
相對的線性的HR behaviors 就是健康而規律的心跳了


2.4.3. Approximate entropy analysis

Approximate entropy (ApEn) is a measure quantifying the regularity and complexity of time series data (Pincus 1991, Pincus & Viscarello 1992, Pincus & Goldberger 1994). Low values of ApEn indicate a more regular (less complex) signal, and high values indicate irregularity (more complex) in signal behavior.

上次提到的ApEn近似熵^^
低的ApEn值表示較規則而不複雜的訊號，而高的值表示不規則而複雜的訊號