  The essential features of far-field low-energy defibrillation are elucidated
using a simple cellular automaton model of excitable media. The model's
topological character allows for direct correspondence with both realistic
models and experiment. An optimal pacing period is shown to arise from the
competition between two effects, and not a resonant response as was previously
hypothesized. Finally, a topologically motivated feedback scheme is presented
that outperforms traditional LEAP by identifying optimal shock timings.
