Catheter Ablation for Atrial Fibrillation: A Review of the Literature

Atrial fibrillation (AF) is the most frequent arrhythmia seen in clinical practice. The incidence of persistent and permanent AF will likely continue to increase as the population ages and as patients with structural heart disease live longer. Until recently, antiarrhythmic medications have been the only commonly employed treatment for maintaining sinus rhythm. However, antiarrhythmic medications have a modest long-term efficacy and the potential for serious side effects. Radiofrequency (RF) catheter ablation is now emerging as a viable alternative to antiarrhythmic medications in maintaining sinus rhythm in patients with AF. A number of different ablation strategies have been used including pulmonary vein isolation, targeting of fractionated electrograms, compartmentalising the atria with linear lesions and various combinations and modifications of these lesion sets. The variation in success within and between techniques suggests that the optimal ablation technique for AF is unclear. The general consensus for patients with paroxysmal atrial fibrillation is to achieve electrical isolation of the pulmonary veins (PVs). In patients with non-paroxysmal AF, PV isolation alone appears to be insufficient. In addition, the structural and electrophysiological changes that have typically occurred at the advanced stage of AF lend greater importance to the identification and ablation of atrial myocardial substrate-driven “sources”. Further efforts are needed to develop better techniques and tools to safely, effectively, and permanently isolate the pulmonary veins, to identify which sites are critical to the maintenance of AF, and to create durable lesions to interrupt intra-arterial reentry. In this review, the rationale and outcomes of rhythm management with drugs and ablation strategies targeting various mechanisms of AF based on our current understanding are discussed.