Although amiodarone maintains sinus rhythm in 45% to 70% of patients during 12 to 54 months follow-up, it is also associated with many serious non-cardiac side effects.  To investigate if episodic treatment with amiodarone could still be effective in preventing atrial fibrillation (AF), but without causing significant side-effects, Ahmed et al. randomised 209 patients with recurrent symptomatic persistent atrial fibrillation to either episodic (drug stopped four weeks after cardioversion and restarted only if patient symptomatic) or continuous amiodarone treatment.

After a median follow-up of 2.1 years, 51 (48%) of those receiving episodic treatement vs 64 (62%) of those receiving continuous treatment had sinus rhythm (P=.05).  AF recurred in 85 patients (80%) of patients treated episodically, compared to 56 (54%) of those treated contuously (p<.001).  No significant difference was noted in the primary composite endpoint of major adverse events related to underlying heart disease or amiodarone (35% vs 33%).  Nonstatistically significant differences in the incidence of amiodarone-related major events (19% episodic vs 24% continuous) and underlying heart disease-related major events (16% vs 9%) were noted.  All-cause mortality and cardiovascular hospital admissions were higher among those receiving episodic treatment (53% vs 34%).

Although the number of patients in this trial is small, the message appears to be that there is no role for PRN amiodarone in the treatment of atrial fibrillation.  If amiodarone side-effects are of concern, then lowering the dose, rather than interrupting therapy, is the preferred strategy.

• Ahmed S, Rienstra M, Crijns HJGM et al.  Continuous vs episodic prohylactic treatment with amiodarone for the prevention of atrial fibrillation: a randomized trial. JAMA 2008; 300:1784-1792.