ADAPTIVE AND PARALLEL SIMULATIONS OF CARDIAC FLUID DYNAMICS AND ELECTROPHYSIOLO

这个子项目是众多研究子项目之一

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. This project aims to perform simulations of cardiac blood-muscle-valve mechanics and electrophysiology, with a long-range goal of performing coupled simulations of mechanics and electrophysiology. Although the equations that describe cardiac mechanics and electrophysiology are different, we employ a common theoretical framework, the immersed boundary (IB) method, for both aspects of heart function. The IB method was introduced as an approach to problems of fluid-structure interaction (e.g., cardiac fluid mechanics), but we have recently extended it to describe cardiac electrophysiology. We have recently developed a unified software implementation of the IB approach to both cardiac mechanics and electrophysiology. This simulation framework provides support for distributed-memory parallelism and spatial adaptivity, thereby allowing us to use modern supercomputers effectively and efficiently. Three-dimensional models of the structure of the heart have been developed by McQueen and Peskin as part of a longterm research effort at the Courant Institute that aims to use simulations of cardiac blood-muscle-valve mechanics to aid in the design of artificial heart valves and other medical devices and therapies. We have recently applied our new adaptive version of the IB method to the first generation of the McQueen/Peskin model of the heart. During this project, we shall perform additional simulations of cardiac mechanics, but replacing this earlier idealized model of the structure of the heart with a recently-developed second generation structural model that is based on CT imaging data. In order to obtain realistic pressures and flow rates efficiently, we shall utilize the adaptive capabilities of our simulation framework to deploy extremely fine computational grids in a localized manner, e.g., in the vicinity of the heart valve leaflets and the vortices shed from these leaflets. Using this same anatomically realistic CT-derived fiber structure, we shall also perform adaptive three-dimensional simulations of cardiac electrophysiology. These models of cardiac mechanics and electrophysiology will ultimately be combined to yield an electro-mechano-fluidic model of the heart, in which the three-dimensional model of the electrical function of the heart will be used to control the timing of the muscle contractions in a realistic manner. Such a simulation platform is required to study treatments for diseases of the heart which crucially involve both aspects of heart function, e.g., dilated cardiomyopathy with dyssynchronous mechanical and electrical activation resulting from bundle branch block, and its treatment via bi-ventricular pacing (cardiac resynchronization therapy). The task of coupling our models of cardiac mechanics and electrophysiology will be simplified by our use of a unified simulation framework for both aspects of cardiac physiology.