Intravenous amiodarone for conversion of atrial fibrillation: misled by meta-analysis?

Therapeutic goals for atrial fibrillation (AF) include ventricular rate control, stroke prevention, conversion to normal sinus rhythm, and maintenance of normal sinus rhythm. The optimal strategy of rate versus rhythm control for acute management of patients with AF is a continuing debate. However, selected patients may require acute treatment with antiarrhythmic agents for conversion of symptomatic AF episodes to normal sinus rhythm. Recently published randomized controlled trials, qualitative systematic reviews, meta-analyses, and evidence-based international consensus guidelines have addressed the controversy regarding acute conversion of AF using antiarrhythmic therapy. Although meta-analyses often provide the highest level of evidence, the validity and application of their results are based on the quality of their methodology and accuracy of reporting. Authors of the most recent meta-analysis of amiodarone for conversion of AF state that the drug is effective and relatively rapid acting in converting AF to normal sinus rhythm in a wide range of patients, and they recommend it as a first-line drug. We feel that these conclusions are overstated and potentially misleading due to methodologic limitations of the analysis. The results of this meta-analysis and others concerning acute conversion of AF should be viewed as hypothesis generating and not the definitive answer to this question. Ultimately, well-designed, adequately powered, randomized placebo- or rate-controlled trials are needed in specific patient populations with AF to determine the absolute benefit of intravenous amiodarone for conversion of AF to normal sinus rhythm. Until more data are available, intravenous amiodarone cannot be promoted as a first-line agent for this purpose.