Progress in Nonpharmacologic Therapy of Atrial Fibrillation

For the past 3 decades, drug therapy has been the mainstay of treatment for patients with atrial fibrillation (AF). In many cases, the therapy is directed at controlling the ventricular response rate, which can be accomplished with a variety of different beta-blockers, calcium channel blockers, and, in fewer cases, with digoxin. In other patients, therapy with several agents is required to suitably slow the ventricular response to acceptable rest and exercise rates. Drugs such as amiodarone and sotalol also may have considerable negative dromotropic affects on the AV node. In other cases, membrane active drugs are used to restore and maintain sinus rhythm. The efficacy of individual antiarrhythmic drug for treating AF has been examined extensively. For example, the Canadian Trial of Atrial Fibrillation (CTAF) trial examined outcomes in patients treated with amiodarone versus propafenone or sotalol.1 At the 1-year mark, 69% of patients treated with amiodarone remained in sinus rhythm, whereas only 39% of those treated with the other two agents were successfully treated1; however, many of these patients had failed to respond to therapy with Class I drugs, however. Similarly, the European and Australian Multicenter Evaluative Research on Atrial Fibrillation Dofetilide (EMERALD) trial showed a 66% response to dofetilide at 1-year followup, when given at a dosage of 500 μg twice daily.2 A host of smaller studies similarly show that only 40% to 60% of patients treated with classic membrane active drugs will remain in sinus rhythm by the end of 1 year.3-12 Enthusiasm for this level of efficacy, however, is tempered by the constitutional side effects, organ toxicity, and proarrhythmic consequences accompanying drug therapy. Up to one third of patients treated with amiodarone develop side effects requiring drug discontinuation over 3 to 4 years of therapy. More recently, two large randomized trials have compared the outcome of treatment with rate control and anticoagulation versus rhythm control plus anticoagulation.13,14 In the Atrial Fibrillation Follow-up Investigation of Rhythm Management (AFFIRM) trial, there was little difference in morbidity or mortality between these two approaches.13 This was despite the observation that normal sinus rhythm was present in 75% to 82% of patients treated with membrane active drugs over 2 to 3 years. As expected, the rate control arm showed sinus rhythm maintenance in only 38% to 42% of patients.13 In 29% of AFFIRM patients, drug therapy was stopped because of side effects. In the companion Rate Control versus Electrical Cardioversion for Persistent Atrial Fibrillation