Vigmond E J, Leon L J
Institute of Biomedical Engineering, University of Montreal, Québec, Canada.
Ann Biomed Eng. 1999 Mar-Apr;27(2):160-70. doi: 10.1114/1.160.
Transmural rotation of cardiac fibers may have a large influence on the initiation, stabilization, and termination of several life threatening cardiac arrhythmias. However, three-dimensional modeling of reentry in cardiac tissue is computationally demanding, as a tissue on the order of centimeters in size must be used to sustain reentry and several seconds must be simulated. Numerical accuracy requires time steps on the order of microseconds and spatial discretization on the order of microns. Consequently, the resultant numerical systems are extremely large. In this article, a computationally efficient model of a three-dimensional block of cardiac tissue with fiber rotation is presented. Computational speedup is achieved by using a discrete cable model which allowed for system order reduction, and also by using a scheme for tracking the activation wave front which identified regions requiring integration with a small time step. Simulating 1.2 s of activity of the approximately 2 x 10(6) cells constituting a block measuring 2.0 x 4.0 x 0.29 cm was performed in 26 h. Effects of model parameters on performance are discussed. The effect of fiber rotation on the spread of electrical activity after point source stimulation and a cross shock protocol is clearly demonstrated.
心肌纤维的透壁旋转可能对几种危及生命的心律失常的起始、稳定和终止产生重大影响。然而，心脏组织中折返的三维建模在计算上要求很高，因为必须使用厘米级大小的组织来维持折返，并且必须模拟数秒时间。数值精度要求时间步长在微秒量级，空间离散化在微米量级。因此，所得的数值系统极其庞大。在本文中，提出了一种具有纤维旋转的三维心脏组织块的高效计算模型。通过使用允许系统降阶的离散电缆模型以及使用一种跟踪激活波前的方案来实现计算加速，该方案可识别需要用小时间步长进行积分的区域。模拟由2.0×4.0×0.29厘米的块组成的约2×10⁶个细胞的1.2秒活动在26小时内完成。讨论了模型参数对性能的影响。清楚地展示了纤维旋转对点源刺激和交叉电击方案后电活动传播的影响。
