Hemodynamic fluctuations and baroreflex sensitivity in humans: a beat-to-beat model.

A beat-to-beat model of the cardiovascular system is developed to study the spontaneous short-term variability in arterial blood pressure (BP) and heart rate (HR) data from humans at rest. The model consists of a set of difference equations representing the following mechanisms: 1) control of HR and peripheral resistance by the baroreflex, 2) Windkessel properties of the systemic arterial tree, 3) contractile properties of the myocardium (Starling's law and restitution), and 4) mechanical effects of respiration on BP. The model is tested by comparing power spectra and cross spectra of simulated data from the model with spectra of actual data from resting subjects. To make spectra from simulated data and from actual data tally, it must be assumed that respiratory sinus arrhythmia at rest is caused by the conversion of respiratory BP variability into HR variability by the fast, vagally mediated baroreflex. The so-called 10-s rhythm in HR and BP appears as a resonance phenomenon due to the delay in the sympathetic control loop of the baroreflex. The simulated response of the model to an imposed increase of BP is shown to correspond with the BP and HR response in patients after administration of a BP-increasing drug, such as phenylephrine. It is concluded that the model correctly describes a number of important features of the cardiovascular system. Mathematical properties of the difference-equation model are discussed.

[1]  M. Turiel,et al.  Power Spectral Analysis of Heart Rate and Arterial Pressure Variabilities as a Marker of Sympatho‐Vagal Interaction in Man and Conscious Dog , 1986, Circulation research.

[2]  R. Cohen,et al.  Hemodynamic regulation: investigation by spectral analysis. , 1985, The American journal of physiology.

[3]  T. G. Coleman,et al.  Mathematical Analysis of Cardiovascular Function , 1985, IEEE Transactions on Biomedical Engineering.

[4]  K H Wesseling,et al.  Effects of peripheral vasoconstriction on the measurement of blood pressure in a finger. , 1985, Cardiovascular research.

[5]  R. D. Boer,et al.  Beat-to-beat blood-pressure fluctuations and heart-rate variability in man: physiological relationships, analysis techniques and a simple model , 1985 .

[6]  J. Strackee,et al.  Comparing Spectra of a Series of Point Events Particularly for Heart Rate Variability Data , 1984, IEEE Transactions on Biomedical Engineering.

[7]  J. Karemaker,et al.  Time delays in the human baroreceptor reflex. , 1983, Journal of the autonomic nervous system.

[8]  The physiology of heart-rate control by arterial baroreceptors in man and animals , 1980 .

[9]  J. Karemaker Vagal effects of the baroreflex on heart rate , 1980 .

[10]  M E Safar,et al.  An evaluation of large arteries compliance in man. , 1979, The American journal of physiology.

[11]  A. Melcher Respiratory sinus arrhythmia in man. A study in heart rate regulating mechanisms. , 1976, Acta physiologica Scandinavica. Supplementum.

[12]  J Davies,et al.  Estimation of the conduction time of the baroreceptor-cardiac reflex in man. , 1973, Cardiovascular research.

[13]  P. Young,et al.  Time series analysis, forecasting and control , 1972, IEEE Transactions on Automatic Control.

[14]  D. J. Cunningham,et al.  Effects of Autonomic Blockade on the Baroreflex in Man at Rest and During Exercise , 1972, Circulation research.

[15]  T. G. Coleman,et al.  Circulation: overall regulation. , 1972, Annual review of physiology.

[16]  P I Korner,et al.  Integrative neural cardiovascular control. , 1971, Physiological reviews.

[17]  Michael D. Geurts,et al.  Time Series Analysis: Forecasting and Control , 1977 .

[18]  G. Pickering,et al.  Reflex Regulation of Arterial Pressure during Sleep in Man: A Quantitative Method of Assessing Baroreflex Sensitivity , 1969, Circulation research.

[19]  D. G. Watts,et al.  Spectral analysis and its applications , 1968 .

[20]  Abraham Guz,et al.  Effect of Changing Heart Rate on Cardiovascular Function in the Conscious Dog , 1966 .

[21]  Joseph W. Linhart,et al.  Effects of Changing Heart Rate in Man by Electrical Stimulation of the Right Atrium: Studies at Rest, during Exercise, and with Isoproterenol , 1965, Circulation.

[22]  K. W. Cattermole Theory and Application of the Z-Transform Method , 1965 .