Phase singularities and termination of spiral wave reentry

In order to elucidate the mechanisms by which a strong shock terminates reentrant wavefronts, we employed phase analysis techniques to study phase singularity dynamics in a finite element model of cardiac tissue. We located postshock phase singularities and traced their movement and survival for sixteen monophasic shocks applied at different times during the rotation of a spiral wave. Our analysis revealed that shocks were more likely to succeed when the number of postshock phase singularities was large. Additionally, phase singularities in regions of the tissue exposed to weak shock-induced electric fields were more likely to survive than those in regions of strong shock-induced fields.