We report on the efficacy and follow-up data of pulmonary vein Isolation using the 23 / 28 mm Arctic Front Cryoballoon (Cryocath Canada), which isolates parts of the venous antrum and venous ostium in patients with atrial fibrillation. The technique is safe and highly effective in treating paroxysmal atrial fibrillation. Acutely we could isolate 100 % of the targeted veins comparable to radiofrequency energy. During a mean follow-up period of 8,5 ± 6 months 57 % of the patients had no recurrence of atrial fibrillation at all. 15 % showed a recurrence only during the first three months. Right phrenic nerve damage is the most common complication, but it recovers within months. Avoidance of phrenic nerve palsy is possible with refined use of different balloon diameters and pacing maneuvers.