Atrial fibrillation: quinidine helps maintain sinus rhythm but increases mortality following cardioversion.

Clinical bottom line (level 1a)

  1. Patients who are cardioverted for chronic atrial fibrillation who receive quinidine are more likely to be in sinus rhythm (NNT = 4 at 12 months) .
  2. However more patients on quinidine die (NNH = 67 at 3 months) .
  3. Side-effects occur in around a sixth of patients on quinidine.
Coplen et al: Circulation 1990; 82 (4): 1106-1116
Expires November 2003

The study

Systematic review of randomised controlled trials of
  • Patients: chronic atrial fibrillation (> 72 hours) undergoing cardioversion (aged 15 to 79; mean 53 in the selected studies)
  • Intervention: quinidine compared with control
  • Outcome: death; maintenance of sinus rhythm (followed for at least 3 months: 90% in the selected studies)


    • Articles found in English and non-English using MEDLINE, 1966 to 1989 (search terms: 'quinidine' and 'atrial fibrillation' or 'atrial flutter' ) and bibliographic references were also searched to find additional papers.

    Selection criteria: as above
    Appraisal criteria: selected and appraised using set criteria (published elsewhere) by 2 independent reviewers.
    Articles excluded if:
    • any other antiarrhythmic agent used except digoxin
    • post-operative patients
    • unclear descriptions of treatment regimens


    Six trials involving 808 patients were included
    No significant heterogeneity noted.

    The evidence

    Outcome Time to outcome CER OR
    (95% CI)    		 NNT
    (95% CI)
    no maintenance of sinus rhythm 12 months /
    (75%)
    ( to )     		-4
    (-7 to -3)
    death 3 months 3/387
    (0.8%)    		 2.98
    (1.07 to 8.33)     		65
    (18 to 1800)

    • adjusted ARR (95% CI) for no maintenance of sinus rhythm is: 24.4% (14.0% to 34.7%)
    • 18% of patients on quinidine experienced side-effects (diarrhoea, syncope and pyrexia). 9% had to discontinue the medication.
    • Only half of patients on quinidine were in normal sinus rhythm at 12 months - this makes the benefits of quinidine even more questionable.

    Comments

    1. There is a possibility that important studies were missed. The search could have been improved by using other databases, contacting some trial coordinators, recognised experts and drugs companies to identify unpublished studies.

    Citation

    1. Coplen SE, Antman EM, Berlin JA, et al: Efficacy and safety of quinidine therapy for maintenance of sinus rhythm after cardioversion: A meta-analysis of randomized control trials. Circulation 1990; 82 (4): 1106-1116
    Search Terms: atrial near fibril* in Cochrane
    Contributor: Nick Shenker and Chris Ball, November 2000
    Reviewer:

    Clinical Question.
    Patient AF
    Intervention or Exposure quinidine
    Comparison control
    Outcome sinus rhythm, side effects, death