ADAPTIVE AND PARALLEL SIMULATIONS OF CARDIAC FLUID DYNAMICS AND ELECTROPHYSIOLO

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 该项目旨在进行心脏血液-肌肉-瓣膜力学和电生理学的模拟，长期目标是进行力学和电生理学的耦合模拟。虽然描述心脏力学和电生理学的方程不同，但我们使用了一个共同的理论框架，即浸没边界(IB)方法，用于研究心脏功能的两个方面。IB方法最初是作为流体-结构相互作用问题(如心脏流体力学)的一种方法引入的，但最近我们将其扩展到描述心脏电生理学。我们最近开发了心脏力学和电生理学IB方法的统一软件实现。这个模拟框架提供了对分布式存储并行性和空间自适应的支持，从而使我们能够有效和高效地使用现代超级计算机。麦昆和佩斯金开发了心脏结构的三维模型，这是库兰特研究所长期研究工作的一部分，该研究旨在利用心脏血液-肌肉-瓣膜力学的模拟来帮助设计人造心脏瓣膜和其他医疗设备和疗法。我们最近将我们新的自适应IB方法应用于第一代McQueen/Peskin心脏模型。在这个项目中，我们将对心脏力学进行更多的模拟，但用最近开发的基于CT成像数据的第二代结构模型来取代先前理想化的心脏结构模型。为了有效地获得真实的压力和流速，我们将利用我们的模拟框架的自适应能力，以局部的方式部署非常精细的计算网格，例如，在心脏瓣膜叶和从这些叶流出的漩涡附近。使用同样的解剖上真实的CT衍生纤维结构，我们也将进行心脏电生理学的自适应三维模拟。这些心脏力学模型和电生理学模型最终将结合在一起，产生心脏的机电流体模型，其中心脏电功能的三维模型将被用来以现实的方式控制肌肉收缩的时间。需要这样一个模拟平台来研究心脏疾病的治疗，这些疾病关键涉及心脏功能的两个方面，例如由束支传导阻滞引起的机械和电活动不同步的扩张型心肌病，以及通过双室起搏(心脏再同步治疗)进行治疗。通过使用心脏生理学两个方面的统一模拟框架，我们将简化心脏力学和电生理学模型的耦合任务。

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.