Abstract and Introduction
Abstract
Atrial fibrillation (AF) is the most common arrhythmia seen in clinical practice, and is associated with increased morbidity and mortality. Management of AF is challenging due to the modest efficacy of antiarrhythmic drug therapies, some of which have significant adverse effects or toxicity. Nonpharmacological treatment of AF, including AF ablation, has recently evolved as an attractive, efficacious and potentially 'curative' therapeutic modality in selected patients. This article reviews various interventional therapeutic options for the management of AF, appropriate patient selection and clinical implications.
Introduction
Atrial fibrillation (AF) is the most common arrhythmia encountered in clinical practice, and is associated with significant morbidity and mortality. AF is often symptomatic, reduces quality of life and increases the risk of stroke fivefold. These detrimental effects of AF are independent of underlying cardiovascular conditions and impose a significant burden on healthcare resources.
Antiarrhythmic drug (AAD) therapy with or without synchronized electric cardioversion has been the mainstay of therapy to restore and maintain sinus rhythm. Randomized data have compared a strategy of rate control to that of rhythm control with antiarrhythmic agents coupled with cardioversion in patients with and without heart failure. Results showed no differences between rhythm and rate control strategies with regard to mortality or morbidity based upon intention-to-treat analysis. However, when data from these trials were analyzed based upon patient's actual rhythm (on-treatment analysis), the presence of normal sinus rhythm was the most powerful independent predictor of overall survival. These findings suggest that sinus rhythm is still preferred over AF, but the means to achieve and maintain normal sinus rhythm with AAD therapy has not shown any morbidity or mortality advantage. This may be due to the known adverse cardiovascular effects of these medications in patients with AF, offsetting the benefits of maintaining normal rhythm. Overall, the AADs were successful in maintaining sinus rhythm in approximately 50% of patients and there was significant crossover between the treatment arms. Finally, a significant number of symptomatic patients with AF were excluded from these clinical trials, many of whom would likely benefit from restoration of normal sinus rhythm. Therefore, there remains the pressing need to develop treatment strategies to restore and maintain sinus rhythm in patients with AF by both pharmacological and nonpharmacological means (Figure 1). These novel strategies may in turn translate into improved cardiovascular outcomes but will need further investigation.
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Figure 1.
Nonpharmacological management of atrial fibrillation. AF: Atrial fibrillation; AV: Atrioventricular; LA: Left atrium; PV: Pulmonary vein; RA: Right atrium.