Pollard A E, Burgess M J, Spitzer K W
Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City.
Circ Res. 1993 Apr;72(4):744-56. doi: 10.1161/01.res.72.4.744.
Three-dimensional membrane-based simulations of action potential propagation in ventricular myocardium were performed. Specifically, the effects of the intramural rotation of the fiber axes and inhomogeneous conductivity on the timing and pattern of epicardial activation were examined. Models were built, with approximately 400,000 microscopic elements arranged in rectangular parallelepipeds in each model. Simulations used the nonlinear Ebihara and Johnson membrane equations for the fast sodium current. Constructed models had histological features of ventricular myocardium. All models were anisotropic. In a subset of the models, an abrupt intramural rotation of the fiber axes was included. This feature was also combined with randomly distributed inhomogeneous conductivity and regions of high transverse resistance to represent nonuniform anisotropy in a further subset of the models. Epicardial stimuli were applied for each simulation. Three-dimensional activation patterns and epicardial isochron maps were constructed from the simulations. We noted that the rotation of fiber axes accelerated epicardial activation distant from the stimulus site. The inhomogeneous conductivity caused regional acceleration and deceleration of activation spread. We also noted features of epicardial activation that resulted from the fiber rotation, and the inhomogeneous conductivity corresponded to that observed in maps from experimental animals.
进行了基于三维膜的心室心肌动作电位传播模拟。具体而言，研究了纤维轴的壁内旋转和电导率不均匀对心外膜激活时间和模式的影响。构建了模型，每个模型中有大约40万个微观元素排列成长方体。模拟使用了用于快速钠电流的非线性Ebihara和Johnson膜方程。构建的模型具有心室心肌的组织学特征。所有模型都是各向异性的。在一部分模型中，纳入了纤维轴的突然壁内旋转。在另一部分模型中，这一特征还与随机分布的电导率不均匀性和高横向电阻区域相结合，以表现非均匀各向异性。每次模拟都施加心外膜刺激。根据模拟构建了三维激活模式和心外膜等时图。我们注意到纤维轴的旋转加速了远离刺激部位的心外膜激活。电导率不均匀导致激活传播的区域加速和减速。我们还注意到由纤维旋转导致的心外膜激活特征，并且电导率不均匀性与实验动物图谱中观察到的情况相符。
