Catheter Ablation for Atrial Fibrillation

everal different approaches have been proposed for targeting the pulmonary veins (PVs) or atria in catheter ablation for atrial fibrillation (AF). It was initially focal radiofrequency (RF) application inside the PV, then PV ostial isolation by segmental RF applications guided by a circular mapping catheter was developed (EP-guided method).1 Another standard method, circumferential PV isolation, was used to disconnect the ipsilateral PVs en bloc by linear RF applications all around the ipsilateral PVs (anatomical method). 2 In both the EP-guided and anatomical methods, the endpoint of the procedure is the electrical isolation of the 4 PVs from the left atrium, which subsequently revealed the limitations of these procedures. The application of RF at the PV ostia can cause PV ostial stenosis or obstruction, which sometimes requires additional angioplastic procedures. Ectopic firing from the myocardium around the PV isolation area often induces postoperative recurrence of AF. Furthermore, perpetuation of AF is induced by reentrant conduction between the PV and the surrounding atrial tissues (venous wave hypothesis). Today, the goal of either method is to isolate all the PVs, not at the ostium but outside the tubular portion (ie, PV antrum) to avoid the risk of venous stenosis and improve the procedural efficacy. That change in the endpoint resulted in an increased rate of cure for the paroxysmal form of AF, ranging from 85% to 95% after approximately 1.5 ablation procedures without antiarrhythmic drugs (AADs).3 The success rate for chronic AF is generally lower than that (70–85%).