Science Publications

Deserranno,D; Kassemi,M; Thomas,JD

Abstract The success and usefulness of lumped cardiovascular models are directlydependent on the physiological fidelity of their formulation. In most existing lumped formulationsfor the heart, the compliance of the chamber is modeled based on its electrical analog, thecapacitor. This has traditionally resulted in the use of a pre-described time-varying stiffnessmodulus for simulating the cardiac contractions. Unfortunately, such a time-varying stiffness doesnot include any physiological contractile machinery and thus no dependency on fiber sarcomere lengthand intracellular calcium concentrations, key mechanisms responsible for proper cardiac function.In this paper a lumped cardiovascular model is presented that is based on the incorporation ofdetailed myofilament activation for simulating the ventricular calcium binding and cross-bridgingmechanism. Upon validation against experimental data, it is shown that the new myofilamentactivation-based model considerably increases the physiological validity andinternal consistency ofthe cardiovascular simulations in comparison to the traditional variable compliance-based models. Itis also shown, through specific case studies, that the present model can serve as a quick responsetool for testing various hypotheses concerning the impact of the calcium binding and crossbridgekinetics on the overall performance of the cardiovascular system.

Keywords Actins; Heart; Microfilaments; Models, Biological

Annals of Biomedical Engineering
0090-6964, Volume 35, Issue 3, 2007, Pages 3-336