way or another the finely tuned balance between conduction velocity and refractory period that is necessary for re-entry formation, as discussed by Rosen MR, et al. [5] among the authors of the Sicilian gambit.These authors recognized that the suppression of arrhythmia mechanisms is much more complex than anticipated.In their own words: And so, we continue to operate in a gray zone, albeit one in which there is more recognition of the complexities that face us than previously was the case.