Hypothesis of transition in two ways from atrial fibrillation to sinus rhythm

A hypothesis of transition from atrial fibrillation to sinus rhythm in close relation with monophasic action potential duration is proposed. The first way: the prolongation of the right atrial refractoriness reduces the wave fronts below a critical number and their collision terminates the arrhythmia. The second way: progressive shortening of refractoriness at a critical level with block and collision of wave fronts.