Continuous vs Episodic Prophylactic Treatment With Amiodarone for the Prevention of Atrial Fibrillation

CONTEXT: Amiodarone effectively suppresses atrial fibrillation but causes many adverse events. OBJECTIVE: To compare major events in patients randomized to receive episodic amiodarone treatment with those who received continuous amiodarone treatment while still aiming to prevent atrial fibrillation. DESIGN, SETTING, AND PARTICIPANTS: A randomized trial of 209 ambulatory patients with recurrent symptomatic persistent atrial fibrillation, conducted from December 2002 through March 2007 at 7 Dutch medical centers. INTERVENTION: Patients were randomly assigned to receive either episodic or continuous amiodarone treatment after electrical cardioversion following amiodarone loading. Episodic amiodarone treatment was discontinued after a month of sinus rhythm and reinitiated if atrial fibrillation relapsed (1 month peri-electrical cardioversion). In the continuous treatment group amiodarone was maintained throughout. MAIN OUTCOME MEASURES: The primary end point was a composite of amiodarone and underlying heart disease-related major events. The secondary end points were all-cause mortality and cardiovascular hospitalizations. RESULTS: After a median follow-up of 2.1 years (range, 0.4-2.5 years), 51 (48%) of those receiving episodic treatment vs 64 (62%) receiving continuous treatment had sinus rhythm (P = .05). There were 85 atrial fibrillation recurrences (80%) among the episodic treatment group vs 56 (54%) in the continuous treatment group (P < .001). No significant difference existed in the incidence of the primary composite end point between each group (37 35% episodic vs 34 33% continuous; incidence rate difference, 0.2; 95% confidence interval CI, -10.2 to 10.6). However, there were nonstatistically significant differences in the incidence of amiodarone-related major events (20 19% episodic vs 25 24% continuous; incidence rate difference, -2.0; 95% CI, -8.7 to 4.6) and underlying heart disease-related major events (17 16% episodic vs 9 9% continuous; incidence rate difference, 3.6; 95% CI, -1.6 to 8.7). All-cause mortality and cardiovascular hospitalizations were higher among those receiving episodic treatment (56 53% vs 35 34%, P = .02). CONCLUSIONS: In this study population, there was no difference in the composite of amiodarone and cardiac major adverse events between groups. However, patients receiving episodic treatment had a significantly increased rate of atrial fibrillation recurrence and a significantly higher rate of all-cause mortality and cardiovascular hospitalizations. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00392431.