Atrial fibrillation: chronic: many patients on amiodarone remained in sinus rhythm following cardioversion.

Clinical bottom line (level 2a)

  1. Around two-thirds of patients with chronic atrial fibrillation who were converted to sinus rhythm and took amiodarone remained in sinus rhythm after 12 months.
  2. Around one-third of patients with chronic atrial fibrillation who were converted to sinus rhythm and took flecainide remained in sinus rhythm after 12 months.
  3. Roughly a tenth of patients who took either drug withdrew due to adverse side-effects.
Zarembski et al: Archives of Internal Medicine 1995; 155: 1885-1891
Expires November 2003

The study

Systematic review of all prospective studies of
  • Patients: with chronic atrial fibrillation (lasting > 2 weeks) refractory to class I antiarrhythmics or sotalol
  • Intervention: amiodarone or flecainide taken for at least 3 months
  • Outcome: maintenance of sinus rhythm (absence of recurrent episodes of AF on Holter monitoring)


    • Articles found in English using MEDLINE, 1983 to 1993 (search terms: no details given ) and Current Contents: Clinical Practice, bibliographies of relevant articles.

    Selection criteria: detailed in text (see above)
    Appraisal criteria: not detailed in text
    Articles excluded if:
    • if analysis incomplete


    Six studies on amiodarone (200-400 mg po daily in 315 patients) and two on flecainide (200 to 300 mg po daily in 163 patients) found.

    The evidence

    outcome time to outcome number of patients/total number %
    (95% CI)
    amiodarone sinus rhythm (at 3 months) ? 217/299 73%
    (68% to 78%)
    amiodarone sinus rhythm (at 12 months) ? 64/107 60%
    (51% to 69%)
    amiodarone discontinued therapy (at 12 months) ? / 9.5%
    (% to %)
    flecainide sinus rhythm (at 3 months) ? 79/191 41%
    (34% to 48%)
    flecainide sinus rhythm (at 12 months) ? 56/163 34%
    (27% to 42%)
    flecainide discontinued therapy (at 12 months) ? 14/163 8.6%
    (4.3% to 13%)

    • No actual numbers were given for patients who discontinued amiodarone at 12 months, only a percentage.
    • Mortality was not reported due to lack of consistent data from the studies.

    Comments

    1. Since there were no randomised comparisons, any true differences between these two drugs are difficult to extrapolate from this systematic review.

    Citation

    1. Zarembski DG, Nolan PE, Slack MK, et al: Treatment of resistant atrial fibrillation: a meta-analysis comparing amiodarone and flecainide. Archives of Internal Medicine 1995; 155: 1885-1891
    Contributor: Chris Ball and Clare Wotton, November 2000
    Reviewer:

    Clinical Question.
    Patient chronic AF
    Intervention or Exposure amiodarone or flecainide
    Outcome maintenance of sinus rhythm