Background: Antiarrhythmic agents enhance maintenance of sinus rhythm(SR) after direct current cardioversion(DCC) for atrial fibrillation but there are few comparative trials. The aims of the study were(1) to establish whether patients successfully cardioverted to SR are more likely to stay in SR over 6 months if taking amiodarone or sotalol, and if so, to establish whether one agent is better than the other;(2) to establish whether taking amiodarone or sotalol is better at achieving chemical cardioversion within the 6 weeks before DCC; and(3) to establish whether DCC is more likely to be successful on a drug. Methods: Randomized, prospective, nonblinded, controlled study of treatment with either amiodarone(n=27), sotalol(n=36), or no antiarrhythmic agent(n=31). Results: Chemical cardioversion occurred in 7 patients in the amiodarone group(A), 7 patients in the sotalol group(S), but none in the no-antiarrhythmic group(N). A total of 33(92%) patients in the sotalol group, 22(81%)patients in the amiodarone group, and 23(74%) patients in the no-antiarrhythmic group were in SR after cardioversion. Of the original cohort of patients, 17(63%) patients in the amiodarone group remained in SR at 6-month follow-up, compared with 14(39%) in the sotalol group and 5(16%) in the no-antiarrhythmic group(A vs N, P< .0002, P< .0006B[after Bonferroni correction]; A vs S, P=.05, P=.15B; and S vs N, P=.03, P=.09B). Conclusions: Amiodarone and sotalol achieved chemical cardioversion before planned electrical cardioversion in 26%and 19%of patients, respectively. After successful cardioversion, amiodarone appears better than sotalol at maintaining SR at 6 months. Background: Antiarrhythmic agents enhance maintenance of sinus rhythm (SR) after direct current cardioversion (DCC) for atrial fibrillation but there are few comparative trials. The aims of the study were (1) to establish whether patients successfully cardioverted to SR are more likely to stay in SR over 6 months if taking amiodarone or sotalol, and if so, to establish whether one agent is better than the other; (2) to establish whether taking amiodarone or sotalol is better at achieving chemical cardioversion within 6 weeks before DCC; (3) to establish whether DCC is more likely to be successful on a drug. Methods: Randomized, prospective, nonblinded, controlled study of treatment with either amiodarone (n = 27), sotalol (n = 31). Results: Chemical cardioversion occurred in 7 patients in the amiodarone group (A), 7 patients in the sotalol group (S), but none in the no-antiarrhythmic group %) patients in the sotalol group, 22 (81%) patient of the original cohort of patients, 17 (63%) patients in the amiodarone group remained in SR at 6-month follow -up, compared with 14 (39%) in the sotalol group and 5 (16%) in the no-antiarrhythmic group (A vs N, P <.0002, P <.0006B [after Bonferroni correction]; A vs S, P = .05, P = .15B; and S vs N, P = .03, P = .09B). Conclusions: Amiodarone and sotalol achieved chemical cardioversion before planned electrical cardioversion in 26% and 19% of patients, respectively. After successful cardioversion, amiodarone appears better than sotalol at maintaining SR at 6 months.