Prospective trials have demonstrated that flecainide, propafenone, quinidine, and sotalol are equally effective in preventing recurrences of atrial fibrillation (AF). A new twice-a-day formulation of propafenone has been demonstrated to have efficacy that is higher than the short-acting form of the drug. Dofetilide, although useful for terminating and preventing recurrence of persistent AF, has limited data establishing efficacy for the prevention of paroxysmal AF. Amiodarone has been demonstrated to be more efficacious than propafenone or sotalol. Trials have demonstrated that subjective adverse effects are less frequent with class IC drugs, sotalol, and dofetilide, compared with class IA antiarrhythmics. In patients who have no evidence of structural heart disease, flecainide, propafenone and d,l-sotalol are the initial drugs of choice based on safety and efficacy concerns outlined in published guidelines. In patients with coronary artery disease (CAD), sotalol, dofetilide, and amiodarone should be used front-line, given their demonstrated safety in survival trials. In patients with left ventricular dysfunction and congestive heart failure, only dofetilide and amiodarone have demonstrated safety based on large prospective survival trials.
AF is the most common cardiac tachyarrhythmia encountered in clinical practice. AF is a disease of aging with over 10% of patients over 80 years old suffering from the disorder.1 The presence of AF is associated with a five-fold increase in morbidity and a two-fold increase in mortality. The majority of morbidity and mortality associated with this arrhythmia are related to complications associated with cerebrovascular embolic events since AF accounts for 75,000 strokes per year in the US. Although AF can be asymptomatic, the majority of patients have symptomatic complaints including palpitations, dyspnea, chest discomfort, and lassitude. These symptoms are often significant enough to adversely affect quality-of-life scores on standardized questionnaires.
The majority of patients with AF have associated structural heart disease, with hypertensive cardiovascular disease being the most frequent cause. However, 20% to 30% of AF cases are labeled as idiopathic or ‘lone’ AF with no discernible cause identified even after extensive evaluation. The choice of antiarrhythmic agent is affected by the presence or absence of significant structural heart disease.2 Safety and efficacy are important considerations in choosing an antiarrhythmic drug for the prevention of AF recurrences. Antiarrhythmic adverse effects include drug-induced proarrhythmia, mortality, bradyarrhythmias, negative inotropy, and subjective and end-organ toxicity.