Long-Term Efficacy of Amiodarone for the Maintenance of Normal Sinus Rhythm in Patients With Refractory Atrial Fibrillation or Flutter

The purpose of this study was to examine the efficacy and safety of amiodarone to maintain sinus rhythm in patients with refractory atrial fibrillation or flutter. One hundred ten patients with atrial fibrillation or flutter, refractory to ≥1 class I antiarrhythmk agents (mean±SD 2.5±1.5, median 2), were given low-dose amiodarone (mean maintenance dose 268±100mg/day) to determine Hs efficacy to maintain normal sinus rhythm after chemical or electrical carcKoversion. Fifty-three patients had chronic and 57 patients had paroxysmal atrial fibrillation or flutter. Mean age of the study population was 60±13 years, and me mean follow-up was 36±38 months (range 31 days to 137 months). Actuarial rates for maintenance of sinus rhythm were 0.87, 0.70, and 0.55 at 1,3, and 5 years, respectively. Twenty-one patients (19%) with arrhythmia recurrence had an increase in amiodarone dose, and after a mean additional follow-up of 2.5 years, 86% remained in normal sinus rhythm. The only observed predictor of atrial fibrillation or flutter recurrence was paroxysmal arrhythmia (40% recurrence vs 9% in patients with chronic atrial fibrillation or flutter; p<0.001). Actuarial rates for withdrawal because of adverse effects were 0.08, 0.22, and 0.30 at 1, 3, and 5 years, respectively. The most frequent adverse effects necessitating withdrawal were skin discoloration (4.5%), pulmonary nbrosis (3.6%; none fatal), and thyroid toxkity (2.7%). No deaths occurred during the study period. In conclusion, amiodarone has a high degree of efficacy for maintaining normal sinus rhythm in patients with atrial fibrillation or flutter, with a relatively low incidence of adverse effects necessitating withdrawal.