Pulmonary vein isolation for atrial fibrillation (AF) has become widely accepted as a therapeutic strategy irrespective of the AF duration. However, the success rates of the first procedure are limited to around 50%-70% in paroxysmal and 40%-50% in persistent AF. 1 Of note, asymptomatic recurrence rate is approximately 50% following catheter ablation. 2,3 Patients with asymptomatic recurrence are at risk of cardiovascular events due to its delayed recognition and physicians' intervention. 4 Implantable loop recorders are recommended to monitor the recurrence of AF following catheter ablation. 5 However, given its invasiveness and high cost, it cannot be recommended for all Japanese candidates for catheter ablation. 6 Thus, methodologies to identify high-risk cohorts have been desired.Several biomarkers, including myocardial injury biomarkers, natriuretic peptides, and serum uric acid, as well as left atrial size, are