Mark S. Link, MD

Amiodarone was associated with higher systemic embolic risk, especially in patients taking warfarin.

Amiodarone is the most frequently used antiarrhythmic drug for atrial fibrillation (AF). On the basis of the AFFIRM trial and some smaller trials, concern has been raised that antiarrhythmics (including amiodarone) are associated with worse clinical outcomes. To examine this issue, researchers conducted an analysis of data from the manufacturer-funded ARISTOTLE trial, in which 17,907 patients with paroxysmal, persistent, or chronic AF were randomized to warfarin or apixaban. Of these patients, 2051 (11.4%) were taking amiodarone at the initiation of the trial.

During a mean follow-up of about 2.7 years, patients on amiodarone had a significantly higher risk for stroke or systemic thromboembolism (1.58% per year vs. 1.19% year; adjusted hazard ratio, 1.47). Although there was a trend to increased mortality with amiodarone (4.76% vs. 4.09%; adjusted HR, 1.16), the difference did not reach statistical significance. Among the patients on amiodarone, apixaban recipients had a lower risk for stroke or thromboembolism than warfarin recipients (1.24% vs. 1.85%; HR, 0.68; 95% confidence interval, 0.40–1.145), but the CI included 1.0. For patients randomized to warfarin, the time in therapeutic range was lower in those on versus those not on amiodarone (56.5% vs. 63.0%; P< 0.0001).

Citation(s):

Flaker G et al. Amiodarone, anticoagulation, and clinical events in patients with atrial fibrillation: Insights from the ARISTOTLE trial. J Am Coll Cardiol 2014 Oct 14; 64:1541.

Viles-Gonzalez JF and Halperin JL.Efficacy and safety of amiodarone in patients with atrial fibrillation in the era of target-specific anticoagulants. J Am Coll Cardiol 2014 Oct 14; 64:1551.