 The purpose of this randomized clinical trial is to compare the efficacy and safety of pulmonary vein isolation with either the second generation cryoballoon Arctic Front AdvanceTM or a radiofrequency ablation technique with an irrigated ablation catheter TactiCathTM Quartz . A total of 128 patients with persistent or longstanding persistent atrial fibrillation will be randomized for either radiofrequency or cryoballoon ablation treatment. With both techniques, pulmonary vein isolation will be performed and confirmed by a circular mapping catheter. The primary endpoint is freedom of any atrial arrhythmia recurrence at 12 months.Treatment success will be evaluated by using 12-lead electrocardiography and 7-day Holter recording. 