Catheter Ablation of Persistent Atrial Fibrillation

Abstract

  Catheter ablation of atrial fibrillation (AF) has been widely accepted as an important therapeutic modality for the treatment of patients with symptomatic, drug-refractory AF. Ablation strategies which target the pulmonary veins (PVs) and/or the PV antrum (segmental or large circumferential lesions) are the cornerstone of AF ablation procedures, irrespective of the AF type. Successful electrical PV isolation results in maintenance of sinus rhythm in 60 to 85% of patients in patients with paroxysmal AF. However, PV isolation is usually insufficient to eliminate persistent or long-lasting persistent AF leading to significantly lower success rate of this method. Up to now, no single strategy is uniformly effective in patients with persistent and long-lasting persistent AF. Many centers follow a stepwise ablation approach including (i) PV isolation as the initial step; (ii) electrogram-based ablation at all sites in the left atrium and the coronary sinus exhibiting complex fractionated atrial electrograms; (iii) If AF sustains, linear ablation (mainly roof and mitral isthmus lines) is then carried out; and (iv) the right atrium and superior vena cava are finally mapped and ablated. However, such an extensive ablation strategy lead to longer procedure time, longer fluoroscopy time, higher complication rates and higher rates of post-procedural atrial tachycardias. Therefore, the risk/benefit ratio of an extensive ablation approach has to be carefully evaluated. Catheter ablation of persistent and long-lasting persistent AF still remains challenging for the electrophysiologists. The long-term efficacy of certain ablation strategies need to be evaluated in randomized trials.