Objective: To observe the efficacy and safety of long term oral administration of small dose amiodarone in the prevention of patients with nonvalvular paroxysmal atrial fibrillation(AF).Methods: Forty-three cases with nonvalvular paroxysmal AF were selected. Amiodarone was decreased from loading dose to maintenance dose (0.05g/d) within one month. Results:The average time of following up was 18 months.The remarkable effective rate of maintenaning sinus rhythm was 53%. Effective rate was 18.6%. The whole e...