On the generation of spiral and scroll waves by periodic stimulation of excitable media in the presence of obstacles of minimum size

In this work we consider the periodic stimulation of two and three dimensional excitable media in the presence of obstacles with an emphasis on cardiac dynamics. We focus our attention in the understanding of the minimum size obstacles that allow generation of spiral and scroll waves, and describe different mechanisms that lead to the formation of such waves. The present study might be helpful in understanding and controlling the appearance of spiral and scroll waves in the medium.