Simulation Of Action Potential Propagation In 2D Tissue Of Atrium

Atrial fibrillation is one of sustained arrhythmia, and many clinical studies have shown that the incidence of atrial fibrillation increases with age. Even so, its pathogenesis is not clear. The virtual heart model with the application of computer is already as a powerful tool to clarify the mechanism of arrhythmia. Virtual heart model can be used as the bridge between the macroscopic pathology and the microscopic origin. And it can go deep into the field which the clinical experiment and biology experiment can’t research to, and realize the quantitative analysis and visualization at any time scale and spatial scale.The complex anatomy of crista terminals and pectinate muscle can provide a substrate for the reentry during the atrial fibrillation. Therefore, this paper simulates the action potential propagation in 2D tissue of atrium including the crista terminals and pectinate muscle cells of rabbits. First of all, based on the action potential formation principle and the conduction of electrical excitation among cells, this paper establishes the action potential model of rabbit right atrial crista terminals and pectinate muscle cells, as well as diffusion model describing the propagation of electrical excitation among the cardiac myocytes. Atrial tissue have the heterogeneity that the APD of crista terminals is longer than the one of pectinate muscle, and the anisotropy that the conduction of electrical excitation along the fiber orientation is the fastest, and the one perpendicular to the fiber orientation is the slowest. Then, this paper establishes the 2D tissue model which contains crista terminals and pectinate muscle cells, and the tissue heterogeneity and anisotropy. Using numerical method such as explicit Euler method, this paper simulates the propagation of action potential in 2D tissue of atrium under the normal pacing rates. In addition, this paper calculates the conduction velocity in the 2D model which is in good agreement with the physiological experimental results, and set up the electrical excitation diffusion coefficient in the model. Finally, this paper simulates the propagation of action potential in 2D tissue of atrium under the pathological case, and the result shows that both the APD of crista terminals and pectinate muscle cells in the model occur oscillations at high pacing rates.This paper uses the C++ programming under the development environment of Microsoft Visual Studio 2010 to designs and realizes the simulation system of the action potential propagation in the 2D tissue. Then this paper shows the simulation results under the MATLAB. Experimental results conform to the physiological significance.