RESUMEN
Objective:To explore the change of dominant atrial cycle length(DACL)for atrial fibrillation waves during the procedure of pharmaceutical defibrillation for persistent atrial fibrillation(AF).Methods:The AF waves had been sampled for thirty patients with persistent AF before and after oral amiodarone loading for 14 days.DACL and the ratio of the power of second peak to power of first peak(P2/P1)for each patient were calculated from frequency spectrum.Results:After 14 days,twenty-one patients restored to sinus rhythm among the thirty patients and the rest 9 patients were still in persistent AF.All patients' DACL was prolonged,but the ratio of P2/P1 was decreased.DACL of 21 patients who restored to sinus rhythm before cardioversion had prolonged more obviously than patients who were under atrial fibrillation.Conclusion:DACL is a useful parameter in judging whether atrial fibrillation has been relieved or not.