Computer generation of fibrillation in a 3-dimensional model of heart

A three-dimensional (3-D) model of electrical propagation in the heart is presented. The model is constructed by discretizing a real dog heart into 1473 cubic elements with 3-mm sides. Each cellular element can be in one of five states: excitable, three relatively refractory, and unexcitable. In the excitable or relatively refractory states an element can propagate, with varying velocities, the electrical excitation in 3-D to its neighbors. Pacing this model results in normal action potentials and propagation, while extrastimulation results in fibrillation. The simulations show that fibrillation results from rapid re-excitation of cellular elements and dispersion refractory states in the cell population.