INTRODUCTION
While pulmonary vein isolation (PVI) is associated with high success rates in patients with paroxysmal atrial fibrillation (PAF),1-4 ablation outcomes in patients with persistent AF (PsAF) are more modest. In patients with PsAF, additional ablation strategies targeting AF substrate demonstrated improved clinical outcomes5. Linear ablation including roof and mitral isthmus (MI) lines6 and electrogram (EGM)-guided ablation7,8 techniques have been widely used in this context. However, the reported outcomes following ablation with these techniques have been variable.9,10 In a previous multicenter randomized trial, additional AF substrate ablation (roof and MI lines or complex fractionated atrial electrogram [CFAE] or EGM-guided) beyond PVI for PsAF was not associated with incremental benefit compared to PVI alone. Importantly, while AF/atrial tachycardia (AT)-free survival rates were relatively low (around 40%), operator bias for linear ablation and CFAE-guided ablation should be considered.11 There is a paucity of data on the relative efficacy of linear ablation and CFAE or EGM-guided ablation for PsAF.11,12 In the present study we compared very long-term clinical outcomes of linear ablation and EGM-guided ablation.