A new mathematical model of the heart based on crossbridge bonds successfully demonstrated the Frank-Starling mechanism and the effects of preload, afterload, and inotropic changes.
A novel mathematical model of ventricular mechanics based on crossbridge dynamics provides a more physiological representation of cardiac function than traditional time-varying elastance models.
Functional descriptions of the heart, especially the left ventricle, are often based on the measured variables pressure and ventricular outflow, embodied as a time-varying elastance. The fundamental difficulty of describing the mechanical properties of the heart with a time-varying elastance function that is set a priori is described. As an alternative, a new functional model of the heart is presented, which characterizes the ventricle's contractile state with parameters, rather than variables. Each chamber is treated as a pressure generator that is time and volume dependent. The heart's complex dynamics develop from a single equation based on the formation and relaxation of crossbridge bonds. This equation permits the calculation of ventricular elastance via E(v) = partial differentialp(v)/ partial differentialV(v). This heart model is defined independently from load properties, and ventricular elastance is dynamic and reflects changing numbers of crossbridge bonds. In this paper, the functionality of this new heart model is presented via computed work loops that demonstrate the Frank-Starling mechanism and the effects of preload, the effects of afterload, inotropic changes, and varied heart rate, as well as the interdependence of these effects. Results suggest the origin of the equivalent of Hill's force-velocity relation in the ventricle.
Palladino et al. (Tue,) conducted a other in Cardiac mechanics. Mathematical model based on crossbridge bonds vs. Time-varying elastance function was evaluated on Computed work loops and ventricular elastance. A new mathematical model of the heart based on crossbridge bonds successfully demonstrated the Frank-Starling mechanism and the effects of preload, afterload, and inotropic changes.