Abstract 148: Observational Study of Efficacy of Low-Dose Amiodarone

Abstract

Importance: Atrial fibrillation (AF) is the most common rhythm abnormality of the heart and is projected to double between 2010 and 2030. Many patients with AF remain symptomatic after rate control with medications and hence need anti-arrhythmic medications to maintain sinus rhythm. Among the multiple medications to prevent AF recurrence, amiodarone (AM) is the most effective. AM and dofetilide are the only 2 medications approved to prevent recurrence of AF in patients with left ventricular dysfunction. Most papers considered “low dose” AM to be between 200 and 300 mg daily. Even a recent review in a major journal recommended maintaining sinus rhythm (SR) with AM 200 to 300 mg daily. Two very small studies from China showed AM 100 mg to be effective. A recent unpublished report by McGrew demonstrated the impressive effectiveness of 100 mg or less of AM to prevent recurrence of AF. Objective: To determine the known AF free interval after first identification of receiving 100 mg AM or less to prevent recurrence of AF. Methods: An observational retrospective chart review of randomly selected adult patients identified to be taking AM 100 mg for AF recurrence for at least 2 months at Charleston Area Medical Center (CAMC) or community clinics during January 1, 2008 to June 30, 2014. Results: Fifty-one patients who were taking AM ≤ 100 mg were identified. Mean duration of apparent AF free continuous treatment was 25.2 ± 23.3 months. AM was decreased in 4% (2 of 51) patients and stopped in 31% (16 of 51) patients for AF recurrence, perceived side effect or unknown reasons. SR was maintained for 25.7 ± 27.7 months. Conclusion: This small study showed that very low dose AM is commonly used in the community and appears to be an effective option for AF prophylaxis. It is important, the providers selecting medications to prevent recurrence of AF be aware of this option.