title: Amiodarone and the risk of bradyarrhythmia requiring permanent pacemaker in elderly patients with atrial fibrillation and prior myocardial infarction.
abstract: OBJECTIVE
  The aim of this study was to determine whether the use of amiodarone in patients with atrial fibrillation (AF) increases the risk of bradyarrhythmia requiring a permanent pacemaker.
  
  
  BACKGROUND
  Reports of severe bradyarrhythmia during amiodarone therapy are infrequent and limited to studies assessing the therapy's use in the management of patients with ventricular arrhythmias.
  
  
  METHODS
  A study cohort of 8,770 patients age > or =65 years with a new diagnosis of AF was identified from a provincewide database of Quebec residents with a myocardial infarction (MI) between 1991 and 1999. Using a nested case-control design, 477 cases of bradyarrhythmia requiring a permanent pacemaker were matched (1:4) to 1,908 controls. Multivariable logistic regression was used to estimate the odds ratio (OR) of pacemaker insertion associated with amiodarone use, controlling for baseline risk factors and exposure to sotalol, Class I antiarrhythmic agents, beta-blockers, calcium channel blockers, and digoxin.
  
  
  RESULTS
  amiodarone use was associated with an increased risk of pacemaker insertion (OR: 2.14, 95% confidence interval [CI]: 1.30 to 3.54). This effect was modified by gender, with a greater risk in women versus men (OR: 3.86, 95% CI: 1.70 to 8.75 vs. OR: 1.52, 95% CI: 0.80 to 2.89). Digoxin was the only other medication associated with an increased risk of pacemaker insertion (OR: 1.78, 95% CI: 1.37 to 2.31).
  
  
  CONCLUSIONS
  This study suggests that the use of amiodarone in elderly patients with AF and a previous MI increases the risk of bradyarrhythmia requiring a permanent pacemaker. The finding of an augmented risk of pacemaker insertion in elderly women receiving amiodarone requires further investigation.
authors.affiliation: Department of Cardiology and Division of Clinical Epidemiology, McGill University Health Center, Montreal, Canada. vidal.essebag@mail.mcgill.ca
authors.forename: Vidal
authors.initials: V
authors.lastname: Essebag
authors.forename: Tom
authors.initials: T
authors.lastname: Hadjis
authors.forename: Robert W
authors.initials: RW
authors.lastname: Platt
authors.forename: Louise
authors.initials: L
authors.lastname: Pilote
mesh_terms: D000368:Aged; D000638:Amiodarone / Q000009:adverse effects* / Q000627:therapeutic use; D000889:Anti-Arrhythmia Agents / Q000009:adverse effects* / Q000627:therapeutic use; D001281:Atrial Fibrillation / Q000150:complications / Q000188:drug therapy*; D001919:Bradycardia / Q000139:chemically induced*; D002304:Cardiac Pacing, Artificial; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D009203:Myocardial Infarction / Q000150:complications*; D012307:Risk Factors; D012737:Sex Factors
chemical_list: D000889:Anti-Arrhythmia Agents; D000638:Amiodarone