A 54-year-old man with paroxysmal atrial fibrillation underwent pulmonary vein (PV) isolation using a 28 mm second-generation cryoballoon catheter. Unexpected electrical superior vena cava (SVC) isolation during cryoballoon application to the right superior PV was observed in the first procedure. Thirteen-months after cryoballoon-based PV isolation, sustained SVC fibrillation was confirmed irrespective of sinus rhythm. Voltage mapping visualized a low voltage area around the SVC was consistent with that around the right superior PV. SVC isolation was obtained by cryoballoon application to the right superior PV and persisted for over a year.