Objective To approach the clinical effects of cardioversion for treatment of atrial fibrillation(AF) in the rheumatic cardial disease patients with large left atrium after valve replacement.Methods All 164 patients with persistent AF after valve replacement(left atrial diameter exceeded 50mm)were randomly divided into 3 groups: amiodarone group(n=20),combination of amiodarone and ramipril group(n=76),and combination of amiodarone and irbesartan group(n=68).Amiodarone was administrated iv in all patients,and cardioversion was used if AF was not returned.Amiodarone was administrated 200mg every day after successful cardioversion,ramipril was used 5mg every day at the same time in ramipril group,irbesartan was used 150mg every day in irbesartan group for 3-6 months.Results Immediate effective ratio was 92.7%(152/164 cases).Mean follow-up was(1.8±0.4) years;128 cases(78.0%) maintained sinus rhythm.Rate of sinus rhythm was 86.8%(66/76 cases) in ramipril group and it was 75.0%(51/68 cases)in irbesartan group with no significant difference between the two groups.It was 55.0%(11/20 cases)in amiodarone group,also without significant difference compared with ramipril or irbesartan group.Left atrial diameter detected in last follow-up significantly exceeded than before cardioversion in amiodarone group((60.5±3.8)mm vs(57.7±4.5)mm,P=0.04);but there was no significant difference between ramipril group((58.2±4.3)mm vs(57.3±5.8)mm,P=0.28)and irbesartan group((57.2.±5.5)mm vs(56.4±4.9)mm,P=0.37).Cardiac function was improved in 3 groups without conspicuous difference among them.Conclusion If methods of cardioversion and combined medicine approach are correct,the effective ratio is high in patients who had long time AF and large left atrium,the rate of maintenance of sinus rhythm is also high,and the cardiac function is improved.Amiodarone combined with ramipril or irbesartan can delay augmentation of left atrium and improve rate of maintenance of sinus rhythm.