A 70-year-old man with atrial fibrillation underwent pulmonary vein (PV) isolation (PVI). Bigeminal concealed PV depolarizations persisted within the right superior PV throughout the PVI. Though the PV depolarizations was suppressed after successful PVI, PV depolarization, following a slow intrinsic PV automatic rhythm, was observed. The coupling interval of the PV depolarizations during the PV automaticity was identical to that of the PV depolarizations during sinus rhythm before the PVI. This case demonstrated that PV depolarization does not always depend on an intact left atrial input, but may depend on some types of triggering electrical activity. © 2008, The Authors.