Cryoballoon ablation has emerged as a novel treatment option for drug-refractory atrial fibrillation (AF). The purpose of this manuscript is to report the initial experience of a Swiss centre performing cryoballoon ablation, and to provide a critical review of the literature. Fourteen patients (age 59 +/- 10 years, LVEF 57 +/- 5%, left atrial size 41 +/- 3 mm) with paroxysmal AF were studied. After transseptal puncture, a 28 mm cryoballoon catheter was inserted into the left atrium. After balloon positioning at the antrum of each pulmonary vein (PV), cryoballoon ablation was performed (5 minutes/application). The endpoint of the ablation was pulmonary vein isolation (PVI). Eighty-four percent of all PVs could be isolated with the cryoballoon alone. There was no specific distribution of the PVs requiring additional non-balloon ablation. The mean procedure time was 199 +/- 56 minutes. One patient developed tamponade requiring drainage. No phrenic nerve palsies occurred. After a period of follow-up of 12 +/- 3 months, 10/14 patients (71%) were in sinus rhythm without antiarrhythmic drugs. A review of AF ablation procedures performed at our centre during a one-year period showed that documentation of persistent AF or other arrhythmias were the causes for not using the cryoballoon in 49% of patients because additional linear lesions may be required in these cases. Cryoballoon ablation is an interesting new tool for PVI. The success rate of 71% after a 1-year follow-up is not higher when compared to radiofrequency ablation. Furthermore, data on long-term outcomes are lacking. Randomised comparisons with radiofrequency catheter ablation are needed.