Atrial fibrillation, commonly associated with rheumatic mitral stenosis, worsens the prognosis. We studied the efficacy of achieving and maintaining sinus rhythm in patients with chronic atrial fibrillation who underwent a successful balloon mitral valvotomy. Fifty-four patients (26 men, 28 women; age 36+/-8 years) received amiodarone 200 mg thrice daily in the first week, and thereafter a maintenance dose of 200 mg once daily. Electrical cardioversion was attempted at 1 and 3 months and patients were followed up at 6, 12 and 18 months. At the end of 1, 3, 6, 12 and 18 months 81 percent, 72 percent, 60 percent, 54 percent and 49 percent of patients, respectively, were in sinus rhythm. Only one patient had a severe adverse effect (hypothyroidism). Univariate analysis revealed that lower age, shorter duration of atrial fibrillation and smaller left atrial size was associated with successful restoration to sinus rhythm. On multivariate analysis, the duration of atrial fibrillation was the only significant predictor of long-term maintenance of sinus rhythm. Amiodarone seems safe and reasonably effective in restoration and maintenance of sinus rhythm in patients of atrial fibrillation with rheumatic heart disease.