My (Alyce's) 91 year old mother was recently experiencing Atrial Fibrillation for the first time and had to be hospitalized.  She had been treated for an aging heart for a while.  The cardiologist planned to shock her heart back into rhythm the following day.  But when he came in the next day he said, “Well, we won’t need to do that because it went back into rhythm on it’s own.”   I (Alyce) asked him, is that a common thing?  He replied, “No, it isn’t.  But it does happen occasionally.”   And it did happen for her!!