title: A baroreflex model of short term blood pressure and heart rate variability.
abstract: Parameters based on heart rate variability alone or on both heart rate and blood pressure variability (baroreflex sensitivity) are becoming increasingly clinical relevant. Nevertheless a complete insight in physiological mechanisms underlying these parameters is still lacking. A computer model may help to fill up some of the gaps. We present a model which consists of a simple beat-to-beat hemodynamic part (Starling heart and Windkessel) linked to a detailed continuous modelled neural control part. The intermediate between continuous and beat-to-beat part is an integral pulse frequency modulator (IPFM) acting as cardiac pacemaker. Input for the IPFM is a "sympathovagal" balance signal, with different dynamics for sympathetic and vagal branches. Low-frequency variability is supposed to arise from resonance of existing noise, while high-frequency variability (respiration) is assumed to enter the closed loop at the hemodynamic (blood pressure) site. Results of three studies have been used for validation: (1) spontaneous variability in heart rate and blood pressure (baroreflex transfer functions), (2) vagal blockade with atropine, (3) a modified Valsalva manoeuvre performed in normal and quadriplegic man. Steady state as well as dynamic properties of the model reasonably well fitted to these experimental data.
authors.affiliation: Dept. of Clinical Physics and Informatics, Vrije Universiteit, Amsterdam, The Netherlands. bj.voorde@azvu.nl
authors.forename: B J
authors.initials: BJ
authors.lastname: TenVoorde
authors.forename: R
authors.initials: R
authors.lastname: Kingma
mesh_terms: D001341:Autonomic Nervous System / Q000502:physiology; D017704:Baroreflex / Q000502:physiology*; D001794:Blood Pressure / Q000502:physiology*; D003198:Computer Simulation; D006339:Heart Rate / Q000502:physiology*; D006439:Hemodynamics; D006801:Humans; D008433:Mathematics; D008955:Models, Cardiovascular