Suppressing arrhythmias in cardiac models with overdrive pacing

Recent findings indicate that fibrillating cardiac tissue arises from spiral wave chaos. Here we show that spiral wave chaos can be suppressed in a cardiac model by pacing the system with low-amplitude, high-frequency current pulses. This overdrive pacing technique is analyzed using a one-dimensional chain and a two-dimensional lattice of coupled, excitable elements with the kinetics described by the Luo-Rudy action potential model (1991). When two-dimensional media were excited with frequencies from 1:1 synchronization region, we found that spiral wave chaos could be suppressed in a limited number of cases. However, when used in conjunction with calcium channel blockers, high-frequency pacing suppressed spiral wave chaos in all episodes. These findings suggest that low-amplitude overdrive pacing in combination with class IV antiarrhythmic drugs, inhibitors of calcium channels, may be useful for eliminating fibrillation in cardiac tissue.