Computational heart-tissue models envelope the solution of non-linear partial and ordinary differential equations which, after applying them certain discretization methods (finite difference, finite element) for its solution, result in a set of operations between matrices in the order of millions which results into programs with high execution times in which the performance of the algorithms is less compared with its parallel version. The current work simulates a human atrium tissue using the Courtemanche electrical model [1]. The cell pairing is made using the finite difference method and its computational implementation was made using the Armadillo C++ library [2], for the sequential version and the acceleration was made through the CUDA library [3] on a nvidia GTX980 card.