Atrial Fibrillation Ablation (CPVA)

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The poor success of pharmacologic therapy for atrial fibrillation (AF) has encouraged many investigators to explore alternative strategies (1-9). Recent randomized studies have demonstrated that ablation strategy is superior to antiarrhythmic drug therapy in patients with paroxysmal/persistent AF (10-12) and more recently even in patients with “chronic” AF (13), but whether this superiority translates into morbidity and mortality benefits remains to be demonstrated into future multicenter trials possibly by uniforming ablation techniques. In the last few years the number of AF ablation procedures is growing worldwide with shorter procedure times resulting in a movement towards inclusion of patients with structural heart disease and long-lasting/permanent AF. Because of the excellent success rates reported by the pioneering groups and the attractiveness of a definitive cure for AF, many patients have begun seeking this curative approach as well as electrophysiologists and centers that offer it according to the new guidelines for AF treatment. From 1999 to 2007 we have performed in Milan at the San Raffaele University-Hospital more than 15,000 AF ablation procedures with an overall long-term success > 90% in paroxysmal/persistent AF and 80% in permanent AF with an acceptably low incidence of major complications. Despite the development of newer technologies and tools, mechanisms of AF are multiple and many of them still remain unknown. Three years ago, we first demonstrated the benefit of vagal denervation in patients with paroxysmal AF undergoing AF ablation and these observations remain a cornerstone in the understanding of AF pathophysiology and treatment. However, at present we need to have more information on pathophysiology of permanent AF to tailor or limit ablation targets since patients with long-lasting or permanent AF require an extensive ablation with repeat procedures. Recent data from our laboratory indicate that progression from first paroxysmal AF to persistent or permanent AF is relatively rapid and can be predicted by clinical variables (14). As a result, identification of subjects at high risk of progression is useful for an optimal ablation timing avoiding a late procedure when AF becomes permanent. Currently, ablation strategies for permanent AF and associated structural heart disease are complex, time consuming, less effective and are associated with higher risk of complications. In the last 2 years pioneering groups have confirmed our previous results even in patients with permanent AF using the stepwise tailored approach, which includes sequential additional ablation targets with repeated procedures to limit or modify the anatomic, electrophysiologic and/or autonomic substrates (15). If substrate elimination is indeed crucial for the outcome, then mapping and navigation systems should be able to exactly visualize the complexity of left atrial anatomy to place lesions accurately avoiding unnecessary and dangerous RF applications to compensate for inaccuracy (Figure 1). The circumferential pulmonary vein ablation or CPVA is the standard procedure as performed in Milan at the San Raffaele University-Hospital. The procedure is performed by manual catheters or remotely by magnetic soft catheters in shorter time as compared with other approaches (16). CPVA consists of large circumferential lesion lines to perform a point-by-point tailored distal disconnection of all PVs, vagal denervation, wide encircled areas with additional standard lesion lines, and non-inducibility of both AF and AT at the end of the procedure. Accumulating data from our laboratory indicate that among patients with paroxysmal/persistent AF without enlarged atria the CPVA alone is associated with an excellent outcome while in patients with longlasting/ persistent or permanent AF and enlarged atria further linear lesions using the least amount of ablation is necessary to achieve non-inducibility.

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