title: Scale invariance in the nonstationarity of human heart rate.
abstract: We introduce a segmentation algorithm to probe the temporal organization of heterogeneities in human heartbeat interval time series. We find that the lengths of segments with different local mean heart rates follow a power-law distribution and show that this scale-invariant structure is not a simple consequence of the long-range correlations present in the data. The differences in mean heart rates between consecutive segments display a common functional form, but with different parameters for healthy individuals and for heart-failure patients. These findings suggest that there is relevant physiological information hidden in the heterogeneities of the heartbeat time series.
authors.affiliation: Center for Polymer Studies and Department of Physics, Boston University, Boston, Massachusetts 02215, USA.
authors.forename: P
authors.initials: P
authors.lastname: Bernaola-Galván
authors.forename: P C
authors.initials: PC
authors.lastname: Ivanov
authors.forename: L A
authors.initials: LA
authors.lastname: Nunes Amaral
authors.forename: H E
authors.initials: HE
authors.lastname: Stanley
mesh_terms: D000465:Algorithms; D018480:Astronauts; D006321:Heart / Q000502:physiology*; D006331:Heart Diseases / Q000503:physiopathology; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D009010:Monte Carlo Method