VENTRICULAR FIBRILLATION, MAPPING AND MODELING

描述(改编自申请人的摘要)：申请人的 总体目标将是阐明心室性心脏病的机制。 使用高分辨率(500电极)组合的纤颤(VF) 测绘和计算机模拟。重点将放在全球，而不是 而不是细胞机制。需要检验的假设是：1.重入 在Wigger的第二阶段VF期间有转子，并负责 维持VF。2.转子的产生和维护取决于 心肌纤维取向及浦肯野纤维的影响 网络。3.需要一个临界质量来维持VF，因为 可再入转子的有限寿命。浦肯野人的角色 将通过在有和没有网络的情况下执行实验来评估网络 普肯野网络使用卢戈尔的解决方案消融。纤维取向 将通过组织病理学检查来确定。这台电脑 模拟研究将基于一个三维模型 使用(改进的)Fitzhugh-Nagumo系统激活心肌 方程式。现有的、详细的有限元模型 犬心的建筑将被用来代表几何图形 和结构(即纤维取向)。模型参数将为 通过在二维和三维空间中拟合模拟的激活模式 测量的正常和折返模式的三维模型 在犬类心脏的小区域进行了定位。我们的模式应该是 外推以模拟整个心脏的整体激活，并使用 研究心脏大小对室性心动过速的影响 与转子数量有关的“质量”假设。该模型将 也可用于研究纤维取向和浦肯野的作用 关于转子形成和维护的网络。

DESCRIPTION (adapted from the applicant's abstract): The applicant's overall objective would be to elucidate the mechanisms of ventricular fibrillation (VF) using a combination of high resolution (500-electrode) mapping and computer simulations. The focus would be on global rather than cellular mechanisms. Hypotheses to be tested are: 1. Reentrant rotors are present during Wigger's stage II VF and are responsible for maintaining VF. 2. The generation and maintenance of rotors depend on myocardial fiber orientation and the influence of the Purkinje fiber network. 3. A critical mass is needed to sustain VF because of the limited life span of the reentrant rotors. The role of the Purkinje network would be evaluated by performing experiments with and without the Purkinje network ablated using Lugol's solution. Fiber orientation would be determined by histopathological examination. The computer simulation studies would be based on a three-dimensional model of myocardial activation using the (modified) FitzHugh-Nagumo system of equations. An existing, detailed finite-element model of the architecture of the canine heart would be used to represent the geometry and structure (i.e. fiber orientation). Model parameters would be obtained by fitting simulated activation patterns in two-dimensional and three-dimensional models to measured normal and reentrant patterns mapped in small regions of the canine heart. The model would be extrapolated to simulate global activation in the whole heart and used to study the effect of heart size on VF and to examine the "critical mass" hypothesis in relation to the number of rotors. The model would also be used to study the role of fiber orientation and of the Purkinje network on rotor formation and maintenance.