Pharmacologic management of atrial fibrillation: established and emerging options

In patients with atrial fibrillation (AF), antiarrhythmic drug therapy currently plays a greater role in maintaining sinus rhythm after cardioversion than it does in converting AF to sinus rhythm. Amiodarone is the most effective antiarrhythmic agent for maintaining sinus rhythm after cardioversion in patients with AF. However, its pharmacokinetics is complex; the drug interacts with many commonly used medications; and long-term use can cause thyroid dysfunction, hepatotoxicity, and other severe extracardiac adverse effects. The use of antiarrhythmic strategies in patients with AF has decreased because of evidence of greater safety and lower costs for hospitalization obtained from the use of rate-control strategies instead. Nevertheless, some patients require a rhythm-control strategy. Warfarin is used to prevent embolic stroke in many patients with AF, but its use is also complex and requires monitoring. Therefore, efforts have been made to develop antiarrhythmic agents with improved tolerability and anticoagulants that are easy to use.

To describe the 3 primary goals of pharmacotherapy in patients with AF, compare and contrast the efficacy and safety of established and investigational pharmacotherapies for AF, and recommend a drug regimen for an individual with AF based on patient-specific factors.

Currently available antiarrhythmic agents differ in their efficacy for maintaining sinus rhythm after cardioversion in AF patients with tolerability problems, comorbidities (particularly heart failure and renal impairment), and potential drug interactions. Hence, when selecting drug therapy to maintain sinus rhythm after cardioversion, it is important to take into consideration patient characteristics, including age, disease states, renal function, and concurrent drug therapies. Outpatient self-administration of single loading doses of flecainide or propafenone with what is referred to as the pill-in-the-pocket approach may be considered for carefully selected patients with recurrent episodes of symptomatic AF. The recently approved antiarrhythmic agent dronedarone has electrophysiologic properties similar to those of amiodarone, but its lack of iodine may improve upon the pharmacokinetic and tolerability issues associated with amiodarone. Vernakalant is another investigational antiarrhythmic agent that may prove useful for cardioversion and maintenance of sinus rhythm after cardioversion in patients with AF. New oral anticoagulants that do not require close laboratory monitoring and are simpler to use than warfarin have been used investigationally for prevention of venous thromboembolism and are in clinical trials for prevention of embolic stroke in patients with AF.

Pharmacotherapy for patients with AF should be individualized based on patient-specific factors. New therapeutic options may become available to facilitate treatment of these patients.