Introduction
The recurrence of atrial fibrillation (AF) can be controlled by the established treatment of pulmonary vein isolation (PVI)1; however, the effect of PVI seems to be insufficient in patients with non-paroxysmal AF. Additional strategies for AF catheter ablation have been considered in previous investigations, and linear ablation of the left atrial (LA) roof line and mitral isthmus (MI) line is one of the additional therapeutic methods of catheter ablation.2 Atrial tachycardia (AT) recurrence has been reported as an undesirable outcome after catheter ablation for AF, which might be attributable to linear ablations.3 Ablation of the LA roof with a cryoballoon in addition to PVI was investigated as a novel method for LA roof line ablation.4 However, detailed clinical outcomes, including the type of recurrence, have not been fully examined. Thus, the present study aimed to clarify the details after catheter ablation in patients with non-paroxysmal AF, especially those who underwent cryoballoon ablation of the LA posterior wall (LAPW) including the LA roof.