Heart Rate Variability, Respiratory Sinus Arrhythmia, and Mathematical Modeling of Acetylcholine Pharmacokinetics/Pharmacodynamics in Sinus Node Neuroeffector Junctions

We studied heart rate (HR), heart rate variability (HRV), and respiratory sinus arrhythmia (RSA) in four male subjects before, during, and after 16 days of spaceflight. The electrocardiogram and respiration were recorded during two periods of 4 min controlled breathing at 7.5 and 15 breaths/min in standing and supine postures on the ground and in microgravity. Low (LF)- and high (HF)-frequency components of the short-term HRV (≤3 min) were computed through Fourier spectral analysis of the R-R intervals. Early in microgravity, HR was decreased compared with both standing and supine positions and had returned to the supine value by the end of the flight. In microgravity, overall variability, the LF-to-HF ratio, and RSA amplitude and phase were similar to preflight supine values. Immediately postflight, HR increased by ∼15% and remained elevated 15 days after landing. LF/HF was increased, suggesting an increased sympathetic control of HR standing. The overall variability and RSA amplitude in supine decreased postflight, suggesting that vagal tone decreased, which coupled with the decrease in RSA phase shift suggests that this was the result of an adaptation of autonomic control of HR to microgravity. In addition, these alterations persisted for at least 15 days after return to normal gravity (1G).

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Respiratory sinus arrhythmia is a major component of heart rate variability in undisturbed, remotely monitored rattlesnakes, Crotalus durissus

Journal of Experimental Biology ◽

10.1242/jeb.197954 ◽

2019 ◽

Vol 222 (9) ◽

pp. jeb197954 ◽

Cited By ~ 4

Author(s):

Pollyana V. W. Sanches ◽

Edwin W. Taylor ◽

Livia M. Duran ◽

André L. Cruz ◽

Daniel P. M. Dias ◽

...

Keyword(s):

Heart Rate ◽

Heart Rate Variability ◽

Respiratory Sinus Arrhythmia ◽

Sinus Arrhythmia ◽

Crotalus Durissus

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One-dimensional, nonlinear determinism characterizes heart rate pattern during paced respiration

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1998.275.3.h1092 ◽

1998 ◽

Vol 275 (3) ◽

pp. H1092-H1102 ◽

Cited By ~ 13

Author(s):

Katrin Suder ◽

Friedhelm R. Drepper ◽

Michael Schiek ◽

Hans-Henning Abel

Keyword(s):

Heart Rate ◽

Time Series ◽

Heart Rate Variability ◽

Respiratory Sinus Arrhythmia ◽

Sinus Arrhythmia ◽

Dynamic Pattern ◽

One Dimensional ◽

Circle Maps ◽

Paced Respiration ◽

Heart Rate Pattern

This study focuses on the dynamic pattern of heart rate variability in the frequency range of respiration, the so-called respiratory sinus arrhythmia. Forty experimental time series of heart rate data from four healthy adult volunteers undergoing a paced respiration protocol were used as an empirical basis. For pacing-cycle lengths >8 s, the heartbeat intervals are shown to obey a rule that can be expressed by a one-dimensional circle map (next-angle map). Circle maps are introduced as a new type of model for time series analyses to characterize the nonlinear dynamic pattern underlying the respiratory sinus arrhythmia during voluntary paced respiration. Although these maps are not chaotic, the dynamic pattern shows typical imprints of nonlinearity. By starting from a piecewise linear model, which describes the different circle maps obtained from the empirical time series for various pacing frequencies, time invariant measures can be introduced that characterize the dynamic pattern of heart rate variability during voluntary slow-paced respiration.

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