Antiarrhythmics for maintaining sinus rhythm after cardioversion of atrial fibrillation.

BACKGROUND: Atrial fibrillation (AF) is the most frequent sustained arrhythmia. AF recurs frequently after restoration of normal sinus rhythm. Antiarrhythmic drugs have been widely used to prevent recurrence, but the effect of these drugs on mortality and other clinical outcomes is unclear. OBJECTIVES: To determine, in patients who recovered sinus rhythm after AF, the effect of long-term treatment with antiarrhythmic drugs on death, stroke and embolism, adverse effects, pro-arrhythmia, and recurrence of AF. SEARCH METHODS: We updated the searches of CENTRAL on The Cochrane Libary (Issue 1 of 4, 2010), MEDLINE (1950 to February 2010) and EMBASE (1966 to February 2010). The reference lists of retrieved articles, recent reviews and meta-analyses were checked. SELECTION CRITERIA: Two independent reviewers selected randomised controlled trials comparing any antiarrhythmic with a control (no treatment, placebo or drugs for rate control) or with another antiarrhythmic, in adults who had AF and in whom sinus rhythm was restored. Post-operative AF was excluded. DATA COLLECTION AND ANALYSIS: Two reviewers independently assessed quality and extracted data. Studies were pooled, if appropriate, using Peto odds ratio (OR). All results were calculated at one year of follow-up. MAIN RESULTS: In this update, 11 new studies met inclusion criteria, making a total of 56 included studies, comprising 20,771 patients. Compared with controls, class IA drugs quinidine and disopyramide (OR 2.39, 95% confidence interval (95%CI) 1.03 to 5.59, number needed to harm (NNH) 109, 95%CI 34 to 4985) and sotalol (OR 2.47, 95%CI 1.2 to 5.05, NNH 166, 95%CI 61 to 1159) were associated with increased all-cause mortality. Other antiarrhythmics did not seem to modify mortality.Several class IA (disopyramide, quinidine), IC (flecainide, propafenone) and III (amiodarone, dofetilide, dronedarone, sotalol) drugs significantly reduced recurrence of AF (OR 0.19 to 0.70, number needed to treat (NNT) 3 to 16). Beta-blockers (metoprolol) also reduced significantly AF recurrence (OR 0.62, 95% CI 0.44 to 0.88, NNT 9).All analysed drugs increased withdrawals due to adverse affects and all but amiodarone, dronedarone and propafenone increased pro-arrhythmia. We could not analyse other outcomes because few original studies reported them. AUTHORS' CONCLUSIONS: Several class IA, IC and III drugs, as well as class II (beta-blockers), are moderately effective in maintaining sinus rhythm after conversion of atrial fibrillation. However, they increase adverse events, including pro-arrhythmia, and some of them (disopyramide, quinidine and sotalol) may increase mortality. Possible benefits on clinically relevant outcomes (stroke, embolisms, heart failure) remain to be established.

Antiarrhythmic drugs for maintaining sinus rhythm after cardioversion of atrial fibrillation: a systematic review of randomized controlled trials.

BACKGROUND: A variety of antiarrhythmic drugs have been used to prevent recurrence of atrial fibrillation after conversion to sinus rhythm. We performed a systematic review to determine the effect of long-term treatment with those drugs on death, embolisms, adverse effects, and atrial fibrillation recurrence. METHODS: We searched MEDLINE, EMBASE, the Cochrane Library (all up to May 2005), and the reference lists of retrieved articles. We included randomized controlled trials that compared any antiarrhythmic against control (placebo or no treatment) or another antiarrhythmic, for more than 6 months. Postoperative atrial fibrillation was excluded. Two evaluators independently reviewed the retrieved studies and extracted all data. Disagreements were resolved by discussion. All results were calculated at 1 year of follow-up. RESULTS: Forty-four trials were included, with a total of 11 322 patients. Several class IA (disopyramide phosphate, quinidine sulfate), class IC (flecainide acetate, propafenone hydrochloride), and class III (amiodarone, dofetilide, sotalol hydrochloride) drugs significantly reduced recurrence of atrial fibrillation (number needed to treat, 2-9), but all increased withdrawals due to adverse effects (number needed to harm [NNH], 9-27) and all but amiodarone and propafenone increased proarrhythmia (NNH, 17-119). Class IA drugs, pooled, were associated with increased mortality compared with controls (Peto odds ratio, 2.39; 95% confidence interval, 1.03-5.59; P = .04; NNH, 109). No other antiarrhythmic showed a significant effect on mortality compared with controls. We could not analyze other outcomes because data were lacking. CONCLUSION: Class IA, IC, and III drugs are effective in maintaining sinus rhythm but increase adverse effects, and class IA drugs may increase mortality.