Atrial fibrillation: paroxysmal: flecainide reduced attacks.

Clinical bottom line (level 1b)

  1. Patients with paroxysmal atrial fibrillation who took flecainide compared with placebo were more likely to be attack-free (NNT = 2 at 8 weeks) .
  2. Attacks took longer to occur with flecainide (mean of 10 days) and the interval between attacks was longer (mean of 17 days).
  3. Patients taking flecainide were more likely to have adverse effects (NNH = 5 at 8 weeks) .
Anderson et al: Circulation 1989; 80 (6): 1557-1570
Expires November 2004

The study

Double-blinded concealed randomised cross-over trial without intention-to-treat
Setting: 16 acute hospitals, USA and Canada

55 patients (aged range 23 to 83 years; mean 56, 63% male) paroxysmal atrial fibrillation (two episodes confirmed on event monitoring)

Excluded if
  • <18 years
  • potentially dangerous symptoms associated with attacks (syncope, angina, transient ischaemic attacks)
  • history of stroke associated with an attack
  • AF caused by a reversible non-cardiac disease
  • acute MI within one month, cardiac surgery within two months
  • severe renal or hepatic failure
  • heart failure (NYHA class III or IV)
  • on antiarrhythmics within last 48 hours, except a stable dose of digoxin
  • significant or symptomatic sick node disease and no pacemaker
  • pregnant or lactating, or insufficient contraception


    • Note:
  • All patients had a 3 week-dosing period with flecainide before randomisation.


    • Control Group: (n = , 24 analysed): placebo
    Experimental Group: (n = , 24 analysed): flecainide initially 100 mg bd increased to 200 mg bd if tolerated

    87% followed for 8 weeks

    The evidence

    Outcome Time to outcome CEREERRRR
    (95% CI)    		ARR
    (95% CI)    		NNT
    (95% CI)
    further attack 8 weeks 20
    (83.3%)    		 9
    (37.5%)    		 55%
    (22% to 74%)    		 45.8%
    (21.4% to 70.3%)    		 2
    (1 to 5)
    adverse effect 8 weeks 20
    (37.7%)    		 30
    (58.2%)    		 -54%
    (-133% to -2%)    		 -20.5%
    (-38.9% to -2.00%)    		 -5
    (-50 to -3)

    Outcome Control Group
    (SD)    		 Experimental Group
    (SD)    		 Mean Difference
    (95% CI)
    mean time to first attack (days) 7.60
    (1.20)     		17.9
    (2.20)     		10
    (9 to 11)
    mean time between attacks (days) 14.8
    (2.70)     		31.7
    (3.30)     		17
    (15 to 19)

    Citation

    1. Anderson JL, Gilbert EM, Alpert BL, et al: Prevention of symptomatic recurrences of paroxysmal atrial fibrillation in patients initially tolerating antiarrhythmic therapy: a multicenter, double-blind, crossover study of flecainide and placebo with transtelephonic monitoring. Circulation 1989; 80 (6): 1557-1570
    Contributor: Chris Ball and Clare Wotton, November 2000
    Reviewer:

    Clinical Question.
    Patient paroxysmal atrial fibrillation
    Intervention or Exposure flecainide
    Comparison placebo
    Outcome further attacks