Comparison of acute and long-term effects of single-dose amiodarone and verapamil for the treatment of immediate recurrences of atrial fibrillation after transthoracic cardioversion.

Aims: Amiodarone and verapamil have been employed to treat immediate recurrences of AF (IRAF) after cardioversion. This study compares the efficacy of these agents for the treatment of IRAF.

Methods And Results: One hundred and eighty-five patients underwent transthoracic cardioversion (CV) for AF. AF recurred within 10 min in 20 patients (10.8%). These patients were randomized to verapamil (seven patients), or amiodarone (13 patients). After administration of verapamil and repeat CV, five patients (71%) experienced IRAF, compared with seven patients (54%) receiving amiodarone (P = 0.4). Including the results after crossover, IRAF occurred in 8/10 patients (80%) who received verapamil, compared with 7/15 patients (47%) who received amiodarone (P = 0.1). The combination of these agents prevented IRAF in 10/20 patients (50%). After a follow-up of 319+/-189 days, 42% of the IRAF patients treated with verapamil and/or amiodarone remained in sinus rhythm, which did not differ from patients without IRAF (53%, P = 0.7).

Conclusions: IRAF occurs in 10% of patients undergoing CV. Amiodarone and verapamil are effective in preventing IRAF and result in a sinus rhythm maintenance rate of 50%. Since there is no difference in the long-term maintenance of sinus rhythm between patients with and without IRAF, attempts to restore sinus rhythm after pharmacological pretreatment are justified.