24 hour heart rate variability analysis based on new methods of non-linear dynamics

Tachograms of two groups, one consisting of 16 cardiac patients with dilated cardiomyopathy (DCM) and the second group consisting of 18 healthy persons as a control group, were investigated. The tachograms were obtained from a commercial Holter ECG system. Artefacts and recognized misclassifications were manually edited and removed. In this study we confirm the effectiveness of methods from non-linear dynamics in the 24 hours analysis of heart rate variability. The methods from symbolic dynamics are useful approaches for classification of the dynamics of heart rate time series. With the help of these methods we can investigate the inner motions of the time series. One interesting aspect of this study is the surprising stability of the renormalized entropy in controls and in DCM patients.