[Beat to beat analysis of morphological difference of ECG waveforms].

Three different kinds of ECG data including the healthy, angina and myocardial infarction from the ECG database were analyzed to obtain the morphological difference sequence of their P-waves, QRS-wave and T-wave, and their RR interval sequences. Then the variability of these four sequences was analyzed by detrended fluctuation analysis (DFA) method. The results indicate that, the changing pattern in the DFA index of RR interval sequence from the healthy to the morbidity is different from those of the P-wave, QRS-wave and T-wave. The DFA indices of the RR interval sequence are about 1 in all three states, while the DFA indices of the other three sequences are about 0.5 in the healthy and all decrease from the healthy to morbidity.