Wavefront-obstacle interactions and the initiation of reentry in excitable media

The combination of the heart's electrical and mechanical activities gives rise to complex dynamics. The reentry, which is one of the most prominent types of heart arrhythmias, is the result of an abnormal electrical activity in the cardiac tissue. These abnormalities are often associated with local non-excitable or partially excitable areas in the cardiac tissue called obstacles. In fact, the proper rhythm for the constriction of cardiomyocytes can be broken by these abnormal obstacles. In this study, we investigate the electrical patterns in a model of excitable media resulting from the interaction between the obstacle and the wavefronts. We consider a slice of cardiac tissue with a rectangular obstacle in vertical and horizontal orientation. Our research reveals that the interaction of the wavefront-obstacle can give rise to reentry and spiral waves. It is also found that a wider section of the obstacle towards the direction of wave propagation causes more deformation in the spatial patterns. In addition, since it can postpone reentry, the continuity of the successive plane waves also determines the resulting spatial patterns.