Cellular automata model of cardiac excitation waves

We present a new computer simulation technology suitable for rapid and quantitatively reliable simulation of propagating excitation waves in anisotropic myocardium. Our model utilizes a finite element or cellular automata (CA) approach in which the elements undergo transitions between a finite number of states (e.g., excited, refractory) according to specific rules. The transition parameter values for the CA elements at each location are computed using the characteristic relations governing propagation at the given point in the tissue, such as the anisotropy ratio and the dependence of the plane wave speed on diastolic interval. The model is well-suited for analysis of arrhythmogenesis and hypothetical therapeutic interventions. Once the effects of an antiarrhythmic drag or disease process on the characteristic relationships have been determined for different cardiac cell types, the electrical activity in tissue with the modified properties can be simulated by our model. In this article, we discuss the basic structure of the model and use it to demonstrate wavelet formation in myocardium with a fixed scar (infarct) in the presence of a sodium channel blocker. This mechanism may help explain the proarrhythmic effects of these agents.