The primary aim of the study is to assess the efficacy of continuous rhythm monitoring with an implantable loop recorder (ILR) compared to conventional ambulatory electrocardiography in detecting episodes of atrial fibrillation after pulmonary vein isolation (PVI). The secondary aim is to assess the efficacy of PVI during a two years follow-up and to assess the reliability of the implantable loop recorder in detecting atrial fibrillation.

50 patients will be enrolled into the study. After enrollment an implantable loop recorder will be implanted at least 6 weeks before scheduled PVI. All patients will be followed for 24 months after PVI. During the follow-up period a 72-hours ambulatory electrocardiographic monitoring will be performed at 1, 6, 12, 18, and 24 months. Transthoracic echocardiography will be performed at enrollment, 3, 12, and 24 months after PVI. Moreover, quality of life will be assessed at baseline, and 6 and 12 months after PVI.

Inclusion Criteria:

• Age => 30 to =< 70 years
• Documentation of paroxysmal atrial fibrillation
• Documentation of persistent atrial fibrillation of < 3 months duration termination either spontaneously or by DC cardioversion
• Scheduled pulmonary vein isolation
• Treatment with at least one class IC or class III antiarrhythmic drug tried

Exclusion Criteria:

• Atrial fibrillation episodes > 3 months or permanent atrial fibrillation
• No indication for pulmonary vein isolation
• Contraindications for anticoagulation treatment
• No informed consent