COMPUTATIONAL METHODS IN CARDIAC FLUID DYNAMICS

这个项目的目标是开发一个工作，收缩， 3-心脏的三维计算机模型，它的瓣膜，和附近的大 船舶. 这种模式将提供一种新的研究工具， 它与临床研究、动物实验和研究并列 in physical物理models模型as a fourth第四mode模式of investigation调查of the heart心脏. 所提出的模型是基于广义的Navier-Stokes方程 粘性不可压缩流体的方程。 在这个概括中， 心肌、瓣叶和大血管壁 由一系列收缩或弹性因素模拟， 在流体中，以局部流体速度运动，并施加力， 在流体上局部。 流体方程在固定的正则条件下求解 计算晶格和移动纤维点耦合到这个 晶格的狄拉克伽玛函数的计算模型。 一旦该模型投入运行，将用于跟踪 在胚胎和胎儿的心脏血流模式，探讨 机械力在发育过程中的作用，以研究 先天性心脏病的血流动力学，以阐明功能 心脏及其瓣膜的解剖学，以确定 心肌在收缩机制上的激活模式， 研究不同区域梗死的机械后果， 通过计算机改进人工心脏瓣膜的设计 测试，并比较天然和人工心脏瓣膜的行为 在紧张的条件下，如运动或疾病。 由于这些研究将在计算机模型中进行， 调查人员将有完全控制每个 计算实验的单个参数，并完全访问 所有计算的变量作为输出。 一些不同的输出模式， 都是三维的 显示血液、瓣膜小叶 和心壁;同样现象的二维电影， 通过心脏的选定横截面平面;以及计算的 压力、流量和腔室尺寸作为时间的函数。 总的来说，这些输出模式将提供一个更详细的视图， 跳动的心脏和它的流动模式比实验上可用的。 同时，为了与临床或实验数据进行比较， 计算机模型还可以生成模拟心音图、超声波 扇形扫描、血管造影、核医学扫描或计算机断层扫描 跳动的心脏的扫描图 总之，拟议的心脏模拟器将是一个多功能的工具， 研究心脏的正常和病理功能， 改进人工心脏瓣膜的设计。

The goal of this project is the development of a working, contractile, 3-dimensional computer model of the heart, its valves, and the nearby great vessels. Such a model will provide a new research tool that should take its place alongside of clinical studies, animal experiments, and research in physical models as a fourthmode of investigation of the heart. The proposed model is based on a generalization of the Navier-Stokes equations of a Viscous, incompressible fluid. In this generalization, the heart muscle, the valve leaflet and the walls of the great vessles are modeled by a collection of contractile or elastic factors that are immersed in the fluid, that move at the local fluid velocity, and that exert forces locally on the fluid. The fluid equations are solved on a fixed regular computational lattice and the moving fiber points are coupled to this lattice by a computational model of the Dirac Gamma-function. Once the model is operational, it will be used to follow the development of the cardiac flow pattern during embryonic and fetal life, to explore the role of mechanical forces during development, to investigate the hemodynamics of congenital heart disease, to elucidate the functional anatomy of the heart and its valves, to determine the influence of the pattern of activation of the myocardium on the mechanics of contraction, to study the mechanical consequences of infarction in different regions of the heart, to improve the design of prosthetic heart valves through computer testing, and to compare the behavior of natural and prosthetic heart valves under under stressful conditions such as exercise or disease. Because these studies will be conducted in a computer model, the investigator will have the advantage of complete control over each individual parameter of the computational experiment and complete access to all computed variables as output. Some different modes of output that will be available from these computer experiments are three-dimensional stereoscopic movies showing the motion of the blood, the valve leaflets, and the heart walls; two-dimensional movies of the same phenomena in selected cross-sectional planes through the heart; and graphs of computed pressures, flows, and chamber dimensions as functions of time. Collectively, these modes of output will give a far more detailed view of the beating heart and its flow pattern than is available experimentally. At the same time, for comparison with clinical or experimental data, the computer model can also generate simulated phonocardiograms, ultrasonic sector scans, angiograms, nuclear medicine scans, or computed tomography scans of the beating heart. In summary, the proposed cardiac simulator will be a versatile tool for investigating the normal and pathological function of the heart and for improving the design of prosthetic heart valves.