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Evidence summaries

Flecainide for Maintaining Sinus Rhythm after Cardioversion of Atrial Fibrillation

Flecainide is more effective than placebo in reducing atrial fibrillation recurrence after cardioversion. It appears to increase risk of proarrhythmia and withdrawals due to adverse effects. Level of evidence: "A"

Summary

A Cochrane review [Abstract] 1 included 59 studies with a total of 20 981 subjects. Flecainide was included in 8 of the studies (n=1 258), and 4 of them compared flecainide with placebo or no treatment.

Flecainide reduced recurrence of atrial fibrillation by about a third (RR 0.65, 95% CI 0.55 to 0.77; 4 studies, n=511) compared to placebo or no treatment corresponding to a recurrence rate of 69.8% in people not treated or receiving placebo and 45.4% (38.4% to 53.8%) in people receiving flecainide. The NNTB for flecainide was 4 (95% CI 3 to 6).

Risk of proarrhythmia (counting both tachyarrhythmias and bradyarrhythmias attributable to treatment) was over 4 times higher among people receiving flecainide than placebo or no treatment (RR 4.80, 95% CI 1.30 to 17.77; 4 studies, n=511) corresponding to a risk of 6 per 1000 among people in the placebo/no treatment group compared with a risk of 30 (95% CI 8 to 112) per 1000 people in the flecainide group. The NNTH for flecainide was 44 (95% CI 10 to 556). Flecainide increased withdrawals due to adverse effects compared to placebo or no treatment (RR 15.41, 95% CI 0.91 to 260.19; 1 study, n=73). Seven people receiving flecainide withdrew due to adverse events, compared with none in the control arm.

Very few data on mortality with flecainide was available; none of the 4 studies (n=511) reported any death from any cause. Thus, it was impossible to make any reliable estimation what the effect of long-term treatment with flecainide on mortality might be. Flecainide has been shown to induce an excess of mortality in some studies in other heart conditions 2.

    References

    • Valembois L, Audureau E, Takeda A et al. Antiarrhythmics for maintaining sinus rhythm after cardioversion of atrial fibrillation. Cochrane Database Syst Rev 2019;(9):CD005049. [PubMed].
    • Echt DS, Liebson PR, Mitchell LB et al. Mortality and morbidity in patients receiving encainide, flecainide, or placebo. The Cardiac Arrhythmia Suppression Trial. N Engl J Med 1991;324(12):781-8. [PubMed]

Primary/Secondary Keywords