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Amiodarone or flecainide for cardioversion in acute onset atrial fibrillation

Three Part Question

In [acute onset atrial fibrillation] is [amiodarone better than flecainide] at [restoring normal sinus rhythm]?

Clinical Scenario

A 50 year old woman presents to the emergency department with acute onset of palpitations of less than two hours duration. She does not have chest pain, her heart rate is about 140-160 with a good systolic blood pressure and respiratory examination is normal. An ECG confirms the rhythm to be atrial fibrillation. You consider which method of pharmacological cardioversion would be most suitable as the medical and cardiological opinions differ between amiodarone and flecainide.

Search Strategy

Medline 1966-11/03 using the Ovid interface.
{[exp Atrial Fibrillation/ OR (atrial adj5 fibrillation).af. OR] AND [exp Amiodarone/ OR OR] AND [exp Flecainide/ OR OR] AND maximally sensitive RCT filter} LIMIT to human AND English language.

Search Outcome

Altogether 42 papers were found of which 4 were directly relevant to the three part question.

Relevant Paper(s)

Author, date and country Patient group Study type (level of evidence) Outcomes Key results Study Weaknesses
Capucci A et al,
62 patients with recent onset atrial fibrillation (<= 7 days), placebo versus amiodarone iv bolus followed by infusion or flecainide poRandomised single blind trialConversion to sinus rhythmAs a percentageSmall numbers Placebo group discontinued monitoring after 8 hours
At 3 hoursPlacebo 29, amiodarone 16, flecainide 68
At 8 hoursPlacebo 48, amiodarone 37, flecainide 91
At 12 hoursAmiodarone 47, flecainide 91
At 24 hoursAmiodarone 89, flecainide 95
Donovan KD et al,
98 patients with acute onset atrial fibrillation (<= 72 hrs), placebo versus amiodarone iv or flecainide ivRCTConversion to sinus rhythmSmall numbers Power not shown
<2 hoursplacebo 7/32, amiodarone 11/32, flecainide 20/34
>2 and <8 hoursplacebo 18/32, amiodarone 19/32, flecainide 23/34
Boriani G et al,
417 patients with recent onset atrial fibrillation (<= 7 days), placebo versus amiodarone iv, flecainide po, propafenone iv or propafenone poCohortConversion to sinus rhythmAs a percentage
At 1 hourPlacebo 9, amiodarone 6, flecainide 13
At 3 hoursPlacebo 18, amiodarone 25, flecainide 57
At 8 hoursPlacebo 37, amiodarone 57, flecainide 75
Martinez-Marcos FJ et al,
150 patients with acute onset atrial fibrillation (<= 48 hrs). Amiodarone iv versus flecainide iv or propafenone ivRandomised single blind trialConversion to sinus rhythmAs a percentage
At 1 hourAmiodarone 14, flecainide 29
At 8 hoursAmiodarone 42, flecainide 82
At 12 hoursAmiodarone 64, flecainide 90


There were no significant differences in the patient groups or adverse effects in all studies. Most adverse effects were mild and self limiting, with no fatal events reported.

Clinical Bottom Line

In the stable patient with acute onset atrial fibrillation and uncompromised left ventricular function, flecainide is the most efficacious drug at restoring normal sinus rhythm expediently. However approximately 60% of patients will revert with no treatment.


  1. Capucci A, Lenzi T, Boriani G et al. Effectiveness of loading oral flecainide for converting recent-onset atrial fibrillation to sinus rhythm in patients without organic heart disease or with only systemic hypertension. Am J Cardiol 1992;70(1):69-72.
  2. Donovan KD, Power BM, Hockings BE et al. Intravenous flecainide versus amiodarone for recent-onset atrial fibrillation. Am J Cardiol 1995;75(10):693-697.
  3. Boriani G, Biffi M, Capucci A et al. Conversion of recent-onset atrial fibrillation to sinus rhythm: effects of different drug protocols. Pacing Clin Electrophysiol 1998;21(11 pt 2):2470-2474.
  4. Martinez-Marcos FJ, Garcia-Garmendia JL, Ortega-Carpio A et al. Comparison of intravenous flecainide, propafenone, and amiodarone for conversion of acute atrial fibrillation to sinus rhythm. Am J Cardiol 2000;86(9):950-953.