Introduction
Although catheter ablation has been established as an important treatment for atrial fibrillation (AF), the outcomes of PVI alone for persistent AF (PeAF) are unsatisfactory. 1-3 Substrate modification to improve outcomes has been performed, and favorable outcomes have been reported for low voltage area (LVA)-guided, linear, and CFAE ablation. 4,5 Nevertheless, some patients remain as non-responders to PeAF catheter ablation in spite of multiple procedures and various ablation strategies. The prevalence of left atrial low-voltage areas (LVAs) is strongly associated with the recurrence of atrial tachyarrhythmias following catheter ablation.6-11 We considered that LVA extent could predict non-responders to PeAF catheter ablation in spite of multiple procedures.