Beyond 1/f: Multifractality in human heartbeat dynamics
Ivanov, PC, Amaral, LAN, Goldberger, AL, Havlin, S, Rosenblum, MG, Struzik, Z, Stanley, HEAIP CONF PROC 511, 273 - 280 (2000)
Abstract
Recent evidence suggests that physiological signals under healthy conditions may have a fractal temporal structure. We investigate the possibility that time series generated by certain physiological control systems may be members of a special class of complex processes, termed multifractal, which require a large number of exponents to characterize their scaling properties. We report on evidence for multifractality in a biological dynamical system - the healthy human heartbeat. Further, we show that the multifractal character and nonlinear properties of the healthy heart rate are encoded in the Fourier phases. We uncover a loss of multifractality for a life-threatening condition, congestive heart failure.