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A Short-Term, Randomized, Double-Blind, Parallel-Group Study to Evaluate the Efficacy and Safety of Dronedarone versus Amiodarone in Patients with Persistent Atrial Fibrillation: The DIONYSOS Study


  • See Appendix for list of investigators and Data Monitoring Committee members.

  • The DIONYSOS trial was funded by sanofi-aventis.

  • Identifier: NCT00489736

  • Dr. Le Heuzey reports honoraria from and advisory board/consultancy relationships with sanofi-aventis, Mede, Medtronic, Boehringer-Ingelheim, Merck Sharp & Dohme, and Beyer. Dr. De Ferrari reports participation in the SEPIA and ATHENA research grants and serving as a consultant for a single meeting on dronedarone. Dr. Zhu reports participation in other research trials funded by sanofi-aventis. Dr. Davy reports serving on the advisory board of sanofi-aventis and receiving honoraria from Merck Sharp & Dohme. Dr. Radzik is an employee of sanofi-aventis and has stock options in the company. Dr. Santini: No disclosures.

Address for correspondence: Jean-Yves Le Heuzey, Cardiologie A et rythmologie, Hôpital Européen Georges Pompidou, 20 Rue Leblanc, 75015 Paris, France. Fax: 33-1-56-09-30-47; E-mail:


Dronedarone versus Amiodarone in Patients with AF. Introduction: We compared the efficacy and safety of amiodarone and dronedarone in patients with persistent atrial fibrillation (AF).

Methods: Five hundred and four amiodarone-naïve patients were randomized to receive dronedarone 400 mg bid (n = 249) or amiodarone 600 mg qd for 28 days then 200 mg qd (n = 255) for at least 6 months. Primary composite endpoint was recurrence of AF (including unsuccessful electrical cardioversion, no spontaneous conversion and no electrical cardioversion) or premature study discontinuation. Main safety endpoint (MSE) was occurrence of thyroid-, hepatic-, pulmonary-, neurologic-, skin-, eye-, or gastrointestinal-specific events, or premature study drug discontinuation following an adverse event.

Results: Median treatment duration was 7 months. The primary composite endpoint was 75.1 and 58.8% with dronedarone and amiodarone, respectively, at 12 months (hazard ratio [HR] 1.59; 95% confidence interval [CI] 1.28–1.98; P < 0.0001), mainly driven by AF recurrence with dronedarone compared with amiodarone (63.5 vs 42.0%). AF recurrence after successful cardioversion was 36.5 and 24.3% with dronedarone and amiodarone, respectively. Premature drug discontinuation tended to be less frequent with dronedarone (10.4 vs 13.3%). MSE was 39.3 and 44.5% with dronedarone and amiodarone, respectively, at 12 months (HR = 0.80; 95% CI 0.60–1.07; P = 0.129), and mainly driven by fewer thyroid, neurologic, skin, and ocular events in the dronedarone group.

Conclusion: In this short-term study, dronedarone was less effective than amiodarone in decreasing AF recurrence, but had a better safety profile, specifically with regard to thyroid and neurologic events and a lack of interaction with oral anticoagulants. (J Cardiovasc Electrophysiol, Vol. 21, pp. 597-605, June 2010)