A total of 88 studies were included, including 34 level I and 13 level II studies.
The methodological flaws identified were as follows: small sample size and a lack of statistical power; populations that were varied and ill-defined; CIs were not reported for the results and there were no data from which they could be calculated; most of the trials had short-term follow-up; and the reporting of adverse reactions was often incomplete.
The following results were from selected, well-designed level I studies only, i.e. randomised placebo-controlled trials (RCTs).
Patients with recent-onset AF (less than 7 days).
The following drugs were effective in converting recent-onset AF to NSR within 24 hours: quinidine (1 RCT), intravenous procainamide (1 RCT), flecainide (3 RCTs), propafenone (9 RCTs), high-dose intravenous amiodarone (1 RCT), a combination of intravenous plus oral amiodarone (1 RCT), and high-dose oral amiodarone (1 RCT).
Patients with recent-onset AF of longer duration (less than 90 days). Intravenous ibutilide (3 RCTs) was effective for converting recent- onset AF of less than 90 days' duration. Confidence intervals were reported for the absolute risk reduction at 90 minutes (95% CI: 27, 29) and the number-needed-to-treat (95% CI: 3, 4).
Patients with AF of longer duration.
The following drugs were effective in converting chronic AF to NSR: oral propafenone (1 RCT), intravenous and oral amiodarone (2 RCTs), and dofetilide (2 RCTs). Compared with placebo, there was no difference in the conversion rates for either propafenone or amiodarone until after 30 days of therapy.
Patients with left ventricular dysfunction.
No studies were identified that exclusively evaluated anti-arrhythmic agents in this group of patients. Dofetilide (subgroup of 2 RCTs): the absolute risk reduction at 72 hours was 20% and the number-needed-to-treat was 5.
Adverse reactions.
In level I trials, there were no differences between the treatment and placebo groups in the rates of minor or major adverse reactions, or withdrawals due to adverse effects. Adverse events associated with individual drug therapies were discussed in the text.