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Chu-Pin Lo

2008-05-16
14:00:00 - 15:00:00

Mechanical and Electrical Activities of Heart

308 , Mathematics Research Center Building (ori. New Math. Bldg.)

Heart is an important organ to work as a pump to control the blood circulation system. Three viewpoints should be made to understand the global function of heart: electrical excitation, mechanical contraction of myocardial muscle, and blood fluid dynamics. In this talk, I will focus on the mechanical and electrical parts. Note that heart is a very complex organ with multiscale phenomena, from microscopic single cell or even molecular ion channel, the mesoscopic tissue, to the macroscopic whole heart. To explore the rich phenomena of heart, some multiscale-coupling mathematical model incorporating both mechanical and electrical effects will be introduced. Such model consists of three components. The first is the bidomain or monodomain electrical equations with strain/stretch effects (mechanical-electrical coupling) on ionic currents, capacitance, and diffusion term. The second is for the electrical-mechanical coupling (so-called Excitation-Contraction Coupling, ECC), including equations describing the production of active stress. The third is the continuum-mechanics based Newton's motion equation with constitutive strain- stress (passive) relation. For the simulation issues, some numerical algorithms will be introduced, e.g. finite element, finite volume, generalized finite difference, and hybrid methods. About the software environment, I will introduce the finite-element based software "Comsol Multiphysics". To build up patient-specific model for clinical diagnosis, the issue about the generation of finite element mesh from the individual biomedical image data such as MRI will be explored. Finally, I will report some research topics in progress, such as the mechanical properties of pulmonary veins sleeves, U wave and Andersen-Tawil syndrome of ECG, and the shifting of SA node leading pacing site.