Atrial fibrillation (AF) recurrence following cardioversion may be due to dispersion of refractoriness and atrial electrical remodeling. Given the temporal changes in refractoriness following cardioversion, it is likely that dispersion of refractoriness following cardioversion is dynamic rather than a static process. If dispersion of refractoriness is dynamic, time would be an important factor in studying the association between dispersion of refractoriness and recurrence of AF. Therefore I hypothesized that a greater change in dispersion of refractoriness, or dispersion instability following cardioversion may be associated with an increase in risk of atrial fibrillation recurrence.