Arrhythmia: amiodarone rarely caused arrhythmias.

Clinical bottom line (level 2a)

  1. Patients on amiodarone were at low risk for developing any arrhythmia (2.8%). Torsade de pointes arrhythmias were rare (0.7%).
  2. There was no clear increase in risk for patients with previous torsade de pointes.
Hohnloser et al: Annals of Internal Medicine 1994; 121 (7): 529-535
Expires November 2003

The study

Systematic review of case reports, case series of > or = 50 patients and follow-up of at least 6 months, controlled studies of
  • Patients: patients (mainly with ischaemic heart disease or dilated cardiomyopathy; 70% presenting with sustained VT or pre-hospital cardiac arrest caused by VF)
  • Intervention: on amiodarone
  • Outcome: subsequent proarrhythmic effects


    • Articles found in English using MEDLINE and Current Contents: Clinical Practice, 1973 to 1993 (search terms: amiodarone, torsade de pointes, proarrhythmia, aggravation of arrhythmia ) and studies were also found using bibliographic references from review articles.

    Selection criteria: as above
    Appraisal criteria: Studies were selected and appraised by 2 independent reviewers (details not given)
    Articles excluded if:
    • incomplete data on type of arrhythmias or amiodarone-associated proarrhythmic effects
    • no clear description of methods or outcomes
    • no English summary


    65 case reports, 17 case series, 7 placebo-controlled trials

    The evidence

    outcome time to outcome number of patients/total number %
    (95% CI)
    any arrhythmia: uncontrolled studies ? 57/2021 2.8%
    (2.1% to 3.5%)
    any arrhythmia: controlled studies ? 0/674 0.00%
    (0.0% to 0.44%)
    torsade de pointes: uncontrolled ? 15/2021 0.7%
    (0.4% to 1.1%)
    in patients with previous torsade de pointes (3 studies): sudden cardiac arrest ? 1/32 3.1%
    (0.0% to 9.1%)
    in patients with previous torsade de pointes (3 studies): recurrent torsade de pointes ? 0/32 0.0%
    (0.0% to 8.9%)

    Comments

    1. The variety of study designs, duration of follow-up and patient mix makes overall estimates difficult. The risk is probably low, but many of the patients had multiple potential causes for arrhythmias.
    2. A recent systematic review has shown that amiodarone reduces all-cause mortality in patients at risk of sudden cardiac death (Sim et al: Circulation (1997): 96: 2823-6 - see Best Evidence).

    Citation

    1. Hohnloser SH, Klingenheben T, Singh BN: Amiodarone-associated proarrhythmic effects: a review with special reference to torsade de pointes tachycardia. Annals of Internal Medicine 1994; 121 (7): 529-535
    Search Terms: atrial fibrill* in Cochrane
    Contributor: Chris Ball and Clare Wotton, November 2000
    Reviewer:

    Clinical Question.
    Patient arrhythmias
    Intervention or Exposure amiodarone
    Outcome subsequent arrhythmias