Nonlinear Dynamics Of The Ecg Rr Sequence Analysis

We can inspect the heart rate variability (HRV) of human by observing heart rate variety. But up to now most methods of analyzing heart rate are still through observing sensibly and statistical analyzing. These methods are too rough to reflect dynamic essence of human heart rate serials (RR serials). So far as a large numbers of study showing, most physiological signal are nonlinear character, most probably so does heart rate of human. So in study of human heart rate, we think, it is important to know whether the heart rate of human has nonlinear character.We will take eighty group RR serials of sufferers which these had Flecainide before and after, and five natural RR serials as sample to more comprehensive nonlinear analysis, We divided a long RR series into short multi-series, worked out the Lempel-Ziv complexity (LZ) and approximate entropy (ApEn). By studying these serials, we get the following results: the square root of the mean squared differences(RMSSD) as nonlinear index, and LZ as nonlinear index can clearly show the effect of medication to restrain the HRV, We discovered that the LZ can clearly show the effect of Flecainide to restrain the HRV of sufferers by comparing LZC and ApEn. Lower RMSSD was observed after taking medicine (p<0.0001), as well as LZ in per segments decreased (p<0.05), but ApEn reflect this unclearly. At the same time, we can calculate some nonlinear parameters like as: correlation dimension, the largest Lyapunov exponent embedded dimension, latency time, we discovered that latency time of human RR serial is in 3～6 stably, the best embedded dimension is in 5～7 scope, attractors of RR serial is strange attractors, correlation dimension in 2～3 scope is fraction dimension, and the value of the largest Lyapunov exponent is positive. All of this can show, RR serials aren't random signals, and aren't simple periodic signal, but are high dimensional chaos obeyed certainly nonlinear orderliness.