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Fractal fluctuations in cardiac time series
B J West1, R Zhang, A W Sanders
1Army Research Office, Research Triangle, NC 27709-2211, USA. westb@aro-emh1.army.mil
Physica A
|September 7, 2001
Summary
Human heart rate fluctuations exhibit long-time memory, behaving as a temporal fractal. This fractal characteristic suggests the cardiac control system possesses allometric properties for environmental adaptation.
Area of Science:
- Physiology
- Complex Systems Science
- Biophysics
Background:
- Human heart rate is a key indicator of systemic circulation, regulated by intricate feedback mechanisms.
- Beat-to-beat heart rate values display continuous fluctuations across diverse timescales.
Purpose of the Study:
- To analyze the correlation properties of beat-to-beat cardiac time series.
- To investigate the underlying mechanisms of heart rate variability (HRV).
- To determine if HRV exhibits fractal properties.
Main Methods:
- Utilized relative dispersion (standard deviation to mean ratio) to analyze cardiac time series data.
- Employed systematic data aggregation to uncover scaling properties.
- Investigated correlations within beat-to-beat heart rate fluctuations.
Main Results:
- Identified the correlation in beat-to-beat cardiac time series as a modulated inverse power law.
- Demonstrated that this scaling property signifies long-time memory in cardiac control.
- Provided evidence that heart rate variability is a temporal fractal.
Conclusions:
- The cardiac control system exhibits allometric properties, enabling adaptation to dynamic environments through scaling.
- HRV's fractal nature points to complex, long-range dependencies in cardiovascular regulation.
- Understanding these scaling properties is crucial for comprehending physiological system dynamics.
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