Influence of forced respiration on nonlinear dynamics in heart rate variability.
Research output: Contribution to journal › Journal article › Research › peer-review
Although it is doubtful whether the normal sinus rhythm can be described as low-dimensional chaos, there is evidence for inherent nonlinear dynamics and determinism in time series of consecutive R-R intervals. However, the physiological origin for these nonlinearities is unknown. The aim of this study was to test whether the known nonlinear input from spontaneous respiration is a source for the nonlinearities in heart rate variability. Twelve healthy subjects were examined in supine position with 3-h electrocardiogram recordings during both spontaneous and forced respiration in accordance with a metronome set to 12 min(-1). Nonlinear dynamics were measured as the correlation dimension and the nonlinear prediction error. Complexity expressed as correlation dimension was unchanged from normal respiration, 9.1 +/- 0.5, compared with forced respiration, 9.3 +/- 0.6. Also, nonlinear determinism expressed as the nonlinear prediction error did not differ between spontaneous respiration, 32.3 +/- 3.4 ms, and forced respiration, 31.9 +/- 5.7. It is concluded that the origin of the nonlinear dynamics in heart rate variability is not a nonlinear input from the respiration into the cardiovascular oscillator. Additional studies are needed to elucidate the mechanisms behind the nonlinear dynamics in heart rate variability.
Original language | English |
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Journal | American Journal of Physiology (Consolidated) |
Volume | 272 |
Issue number | 4 Pt 2 |
Pages (from-to) | R1149-54 |
ISSN | 0002-9513 |
Publication status | Published - 1997 |
Bibliographical note
Keywords: Adolescent; Adult; Female; Heart Rate; Humans; Male; Middle Aged; Models, Biological; Nonlinear Dynamics; Respiration; Respiratory Mechanics; Supine Position; Time Factors
ID: 8420713