Abstract:
This paper presents the development and validation of a sophisticated, three-dimensional computer model designed to simulate the biomechanics and electrophysiology of electrical conduction in the human atria. Unlike previous, simpler representations, this model incorporates an anatomically realistic geometry of both the left and right atria, including key muscle bundles like the crista terminalis, pectinate muscles, and Bachmann's bundle. The spread of electrical current is simulated using a monodomain model solved with the finite volume method, coupled with a realistic model of human atrial cell membrane kinetics. A central feature of the model is its representation of the physical properties of the tissue. Muscle bundles are modeled as anisotropic structures, with different conductivity values assigned to reflect faster electrical propagation along the fiber axis compared to the transverse direction. The model was validated by simulating a normal sinus rhythm and comparing the resulting activation patterns and local conduction velocities to published experimental data. The simulations successfully demonstrated the critical role of the fast-conducting bundles in shaping the global wavefront propagation and provided conduction velocities (e.g., 110-177 cm/s in bundles, ~74 cm/s in bulk tissue) that align well with experimental findings. This validated biophysical model provides a powerful new tool for investigating both normal and abnormal atrial conduction, such as flutter and fibrillation, in a detailed, anatomically accurate framework.
