This paper reports the results of a theoretical investigation of spiral wave breakup in model
equations of action potential propagation in cardiac tissue. A general formulation of these
equations is described in which arbitrary experimentally determined restitution and
dispersion curves can in principle be fitted. Spiral wave behavior is studied in two‐
dimension as a function of a parameter Re which controls the steepness of the restitution
curve at short diastolic intervals. Spiral breakup is found to occur when the minimum period …