TY - JOUR

T1 - Influence of forced respiration on nonlinear dynamics in heart rate variability.

AU - Kanters, J K

AU - Højgaard, M V

AU - Agner, E

AU - Holstein-Rathlou, N H

N1 - Keywords: Adolescent; Adult; Female; Heart Rate; Humans; Male; Middle Aged; Models, Biological; Nonlinear Dynamics; Respiration; Respiratory Mechanics; Supine Position; Time Factors

PY - 1997

Y1 - 1997

N2 - 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.

AB - 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.

M3 - Journal article

C2 - 9140014

VL - 272

SP - R1149-54

JO - American Journal of Physiology - Cell Physiology

JF - American Journal of Physiology - Cell Physiology

SN - 0363-6143

IS - 4 Pt 2

ER -