Background: The relationship between pulmonary vein (PV) potential (PVP) disappearance patterns during encircling ipsilateral pulmonary vein isolation (EIPVI) of atrial fibrillation (AF), and outcome was examined. Methods and Results: A total of 352 consecutive AF patients (age, 61±12 years; 269 men, 76.4%; paroxysmal AF, n=239; persistent AF, n=73; and long-standing persistent AF, n=40) who underwent initial AF ablation were studied. After EIPVI with a double Lasso technique, pacing was performed from the PV carina to confirm isolation of the carina. PVP disappearance patterns were classified into 3 types: A, both superior and inferior PVP disappeared simultaneously; B, superior and inferior PVP disappeared separately; and C, additional RF applications were required inside the encircling lesions to eliminate the PVP after creating anatomical encircling lesions. The relationship between these patterns and outcome was examined. Six groups were defined according to the combination of right and left ipsilateral PVP disappearance patterns. The incidence of A-A, A-B, B-B, A-C, B-C, and C-C was 7.1%, 14.2%, 16.2%, 15.3%, 27.3%, and 19.9%, respectively. AF recurrence-free rate at 2 years for these 6 groups was 96%, 81%, 78%, 64%, 64%, and 59%, respectively (P<0.02). The incidence of a carina isolation was 153/154 (99.4%) for type A, 221/259 (85.3%) for type B, and 145/290 (50.0%) for type C. Conclusions: PVP disappearance pattern during EIPVI was significantly associated with the incidence of residual PV carina conduction and AF recurrence.