Wavelet and wavelet packet decomposition of RR and RTmax interval time series

As a novel approach for analyzing ECG as time series, wavelet packet decomposition is presented as being an advanced and versatile signal decomposition scheme. An optimized wavelet packet decomposition is selectezwith respect to the minimization of the entropy of time series. Signal decomposition schemes are visualized by tree structures, and an optimized structure is called a best tree. Examples of RR and RT_max interval time series are analyzed by both wavelet and wavelet packet method. The accuracy of RT_max interval variability measurement was improved by oversampling the acquired ECG signal.