AJP - Heart and Circulatory Physiology, Vol 249, Issue 3 560-H569, Copyright © 1985 by American Physiological Society
Modeling of time-variant coupling between left ventricle and aorta in cardiac cycle
A. Tozeren and S. Chien
An analytical model is developed to study the interaction between the left
ventricle and vascular system. Ventricular pressure is expressed as a
function of the chamber volume, volumetric strain rate, and the degree of
activation. A three-element Wind-kessel model is employed to represent the
hydraulic properties of the vascular system. Conditions of interaction
between the left ventricle and the vascular system are formulated in
mathematical terms. Numerical solutions are obtained for the mechanical
events occurring during a cardiac cycle as a function of time. The time
variations of aortic pressure and ventricular volume predicted by the model
compare well with the experimental results of Sunagawa and co-workers [Am.
J. Physiol. 243 (Heart Circ. Physiol. 12): H346-H350, 1982, and Am. J.
Physiol. 245 (Heart Circ. Physiol. 14): H773-H780, 1983]. Furthermore, the
application of the present model to the experimental data has allowed the
derivation of the intrinsic contractility parameters in these experiments.
The unique features of this analytical model are that 1) it provides the
time-variant pressure and volume curves of the left ventricle in relation
to the aorta, 2) it generates information on the effects of heart rate on
these hemodynamic parameters, and 3) it allows the derivation of intrinsic
contractility parameters from experimental data.
