Oral Amiodarone for Acute Cardioversion of Atrial Fibrillation Study

Background: Atrial fibrillation (AF) is estimated to affect over 33 million people worldwide and is often associated with significant co-morbidities such as myocardial infarction, heart failure, dementia, and embolic stroke. Consequently, AF poses a significant burden to the healthcare system, in both direct and indirect costs of disease.

The management of AF in the acute setting is complex, especially for patients who suffer from persistent AF, defined as sustained AF for > 7 days. While one possible treatment strategy involves allowing AF to continue whilst controlling the ventricular rate (i.e. rate control), in certain cases, it is preferable to terminate the AF and restore normal sinus rhythm (i.e. rhythm control) for relief of intolerable symptoms associated with AF.

There are several methods currently in use for rhythm control, including observation without intervention, use of oral and/or intravenous anti-arrhythmic drugs for pharmacological cardioversion, and electrical cardioversion. However, each of these strategies come with significant limitations. Amiodarone was originally developed for treatment of angina, but is now widely recognized for its anti-arrhythmic properties. Current American College of Cardiology/American Heart Association/European Society of Cardiology guidelines recommend the use of amiodarone as a cardioversion agent in both intravenous and oral administration. Furthermore, the use of oral amiodarone is considered the standard of care for rhythm management in AF. Prior studies have demonstrated that the administration of a single, oral converting dose of amiodarone has similar rates of sinus rhythm conversion at 24 hours post-intervention compared to Vaughan-Williams Class 1C anti-arrhythmic medications. The use of amiodarone as a first-line therapy for AF is appealing when considering its safety profile.

Objectives: To determine the safety and efficacy of high-dose amiodarone, given as a single uniform oral dose, for the treatment of acute AF in a hospital inpatient setting and acute persistent AF in an outpatient ambulatory clinic.

Methods: This study will be a double-blind randomized controlled trial in patients with symptomatic AF. Amiodarone and placebo capsules will be prepared in single dose packs. A single dose pack will consist of either 2000 mg of amiodarone hydrochloride crushed and placed in 10 gel capsules of 200 mg each, or 10 gel capsules of crushed placebo. Individual dose packs will then be randomly assigned to participants with a unique research number.