Beyond 1/f: Multifractality in human heartbeat dynamics.

Ivanov, PC, Amaral, LAN, Goldberger, AL, Havlin, S, Rosenblum, MG, Struzik, Z, Stanley, HE.
AIP CONF PROC 511, 273-280 (2000)

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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.