Intermittency in spiral defect chaos increases mean termination time

Spiral defect chaos (SDC), characterized by the continuous creation and annihilation of spiral waves are thought to underlie atrial fibrillation. While in the SDC state, the number of spiral waves fluctuates and drops to zero leading to termination of the chaotic waves. In this work, we report a dynamical state, SDC punctuated by intermittency upon varying a single parameter in our reaction-diffusion system, analogous to the intermittency behavior observed in fluid systems. This change in the parameter allows the system to transition from SDC to a single spiral wave, passing through an intermediate regime of intermittency. This dynamical state is characterized by, intervals of SDC that are sandwiched between non-SDC intervals during which the number of spiral waves remain small and constant. We show that the mean termination time increases significantly as the control parameter pass through intermittency regime and quantify this intermittency. In the intermittent parameter regions exhibiting SDC, we observe quasistable spiral waves persisting intermittently in part of the computational domain. These results may have implications for clinical atrial fibrillation, which often shows intermittency, switching back-and-forth between fibrillation and normal sinus rhythm.