THE UNSTABLE PERIODIC ORBITS EMBEDDED IN HEART VARIABILITY OF HEALTHY SUBJECTS
健康人心率变异性中的不稳定周期轨道

To characterize the deterministic dynamics in heart rhythm, the unstable periodic orbit analysis were the RR interval time series of healthy young men. The unstable periodic orbits (UPO) with statistical significance and the hierarchies of UPOs(period 1, period 2, period 3 and period 4) have been extracted from the heart rhythm. It suggests that in healthy young men, the dynamics of normal heart rhythm contains significant deterministic components. Furthermore, the inherent non-stationary of the heart rhythm can be shown by developing of period 1 orbit. The results provide further evidences to verify that chaos dynamics exists in heart rate variability.