title: Amiodarone versus placebo and class Ic drugs for cardioversion of recent-onset atrial fibrillation: a meta-analysis.
abstract: OBJECTIVE
  This meta-analysis compared amiodarone with placebo and class Ic drugs for the cardioversion of recent-onset atrial fibrillation (AF), defined as lasting less than seven days.
  
  
  BACKGROUND
  Despite the lack of trials that support its efficacy convincingly, amiodarone is widely used for conversion of recent-onset AF.
  
  
  METHODS
  We searched Medline and EMBASE databases, as well as the Cochrane Controlled Trials Register for randomized trials on recent-onset AF comparing amiodarone to placebo or class Ic drugs. Data were combined according to a fixed effect model. The primary end point was the rate of conversion at 24 h. To study time-dependency of the drugs, efficacy at 1 to 2 h, 3 to 5 h, 6 to 8 h, and at 24 h was analyzed.
  
  
  RESULTS
  We found six studies randomizing amiodarone versus placebo (595 patients) and seven studies versus class Ic drugs (579 patients). There was no significant difference between amiodarone and placebo at 1 to 2 h, but significant efficacy was found after 6 to 8 h (relative risk [RR] 1.23, p = 0.022) and at 24 h (RR 1.44, p < 0.001). Efficacy with amiodarone was inferior to class Ic drugs for up to 8 h (RR 0.67, p < 0.001) but no difference was seen at 24 h (RR 0.95, p = 0.50). There were no major adverse effects.
  
  
  CONCLUSIONS
  Amiodarone is superior to placebo for cardioversion of AF, and even though the onset of conversion is delayed, its efficacy is similar at 24 h compared with class Ic drugs. These results favor amiodarone as a reasonable alternative for patients with recent AF in whom class Ic and other, more rapidly acting antiarrhythmic drugs cannot be used.
authors.affiliation: Département de cardiologie et de soins intensifs, Hôpital Louis Pradel, Lyon, France. philippe.chevalier@chu-lyon.fr
authors.forename: Philippe
authors.initials: P
authors.lastname: Chevalier
authors.forename: Alexis
authors.initials: A
authors.lastname: Durand-Dubief
authors.forename: Haran
authors.initials: H
authors.lastname: Burri
authors.forename: Michel
authors.initials: M
authors.lastname: Cucherat
authors.forename: Gilbert
authors.initials: G
authors.lastname: Kirkorian
authors.forename: Paul
authors.initials: P
authors.lastname: Touboul
mesh_terms: D000328:Adult; D000368:Aged; D000638:Amiodarone / Q000008:administration & dosage / Q000627:therapeutic use*; D000889:Anti-Arrhythmia Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D001281:Atrial Fibrillation / Q000188:drug therapy*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016032:Randomized Controlled Trials as Topic; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D000889:Anti-Arrhythmia Agents; D000638:Amiodarone