BackgroundAlthough circumferential pulmonary vein isolation (CPVI) catheter ablation may not be sufficient for long‐standing persistent atrial fibrillation (L‐PeAF), it is not clear which ablation strategy is beneficial in addition to CPVI. We sought to investigate whether additional complex fractionated atrial electrogram (CFAE)‐guided ablation improves clinical outcomes in L‐PeAF patients who exhibit continuous atrial fibrillation (AF) after CPVI and linear ablation (Line).Methods and ResultsThis study enrolled 137 L‐PeAF patients (71.4% male, 61.6±10.9 years old) who underwent radiofrequency catheter ablation. We conducted CPVI+Line based on the Dallas lesion set (posterior box+anterior line) after baseline CFAE mapping in all patients. If AF was defragmented (terminated or changed to atrial tachycardia), the procedure was stopped (AF‐Defrag group, n=29). If AF was maintained after CPVI+Line, we mapped the CFAE again and randomly assigned the patient to the CPVI+Line group (n=54) or the additional CFAE ablation group (CPVI+Line+CFAE group, n=54). L‐PeAF was defragmented during CPVI+Line in 21.2% of patients (29/137, AF‐Defrag group). The mean CFAE cycle length was prolonged (P<0.001), and CFAE area (CFAE cycle length <120 milliseconds) was reduced (P<0.001) after CPVI+Line in the remaining patients. Procedure time was longer in the CPVI+Line+CFAE group than the CPVI+Line group (P=0.023), but procedure‐related complication rates did not vary. During 22.3±13.2 months of follow‐up, the clinical recurrence rates were 17.2% in the AF‐Defrag group, 18.5% in the CPVI+Line group, and 32.1% in the CPVI+Line+CFAE group (log rank, P=0.166).ConclusionsAlthough CPVI+Line reduces and localizes CFAE area, additional CFAE ablation after CPVI+Line does not improve the clinical outcomes of catheter ablation in patients with L‐PeAF.