Computational modeling of electromechanical coupling of left ventricle

Abstract

Cardiovascular diseases are the leading cause of death in the world. They reduce the life quality and consume almost a trillion dollars in health-care expenses in Europe and the United States alone. Computational modeling and simulation technologies hold promise as important tools to improve cardiac care and are already in use to elucidate the fundamental mechanisms of cardiac physiology and pathophysiology. In this chapter, detailed computational modeling of electromechanical coupling for the left ventricle is presented. A computational platform in the SILICOFCM project was developed using state-of-the-art finite element modeling for macro-simulation of fluid-structure interaction with micro-modeling at the molecular level for drug interaction with the cardiac cells. In this chapter, fluid-solid coupling for the left ventricle was introduced. A nonlinear material model for the heart wall using constitutive curves that include the stress-strain relationship was presented. A monodomain model of the modified FitzHugh-Nagumo model of the cardiac cell was used. Six electrodes are positioned at the chest to model the precordial leads and the results are compared with real clinical measurements. The inverse ECG method was used to optimize the potential on the heart. A whole heart electrical activity in the torso embedded environment, with spontaneous initiation of activation in the sinoatrial node, incorporating a specialized conduction system with heterogeneous action potential morphologies throughout the heart was presented. Body surface potential maps in a healthy subject during progression of ventricular activation in nine sequences were used. The results with a parametric and realistic model of the left ventricle where PV (pressure/volume) diagrams depend on the change of Ca2+, elasticity of the wall, and the inlet and outlet velocity profiles have been presented. It directly affects the ejection fraction. The presented approach with variation of LV geometry and simulations, which include the influence of different parameters on the PV diagrams, is directly interlinked with drug effects on heart function. This work is in continuous progress and it includes the incorporation of different drugs that directly affect the cardiac PV diagrams and ejection fraction (e.g., angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, nitrates, diuretics, calcium channel blockers). A computational platform such as SILICOFCM for sure will open a new avenue for in silico clinical trials as well as a new tool for risk prediction of cardiac disease in specific patients using drug therapy.