Antecedents: electrical isolation of pulmonary veins is the standard treatment for patients with atrial fibrillation. However, its efficacy is lower in persistent and chronic forms of this arrhythmia compared to paroxysmal atrial fibrillation. Many complementary techniques have been proposed, that added to pulmonary veins isolation, may reduce the recurrence rate of atrial fibrillation. However, none of them has obtained consistent results. Linear ablation aims to parcellate and modify the left atrial substrate responsible for atrial fibrillation maintenance. Previous studies have offered contradictory results using linear ablation.

Methods: SUPAFER is a multicenter, 1:1 randomized clinical trial that compares the efficacy of pulmonary veins isolation alone vs pulmonary vein isolation plus an specific protocol of left atrial linear ablation. Contrary to previous studies, the specific SUPAFER linear ablation is systematic, homogeneous and target atrial areas that have not been systematically ablated in previous trials. The trial aims at demonstrating the superiority of the combined ablative approach during 1-year follow-up. Daily transtelephonic ECG samples a 30 days continuous ECG monitoring are used to maximize de detection of recurrences, even asymptomatic.

Inclusion Criteria:

• Persistent atrial fibrillation documented with electrocardiogram and defined as: persistent (continuous AF duration >1 week) or long-lasting persistent (continuous AF duración >1 year).
• One of the following additional criteria: 1)symptomatic AF, 2)recurrence despite antiarrhythmic drugs or after electrical cardioversion, 3)tachymiopathy, 4)heart failure, 5)antiarrhythmic drugs either not tolerated or rejected or considered inadequate by the patient or an electrophysiology specialist, 6)preference for ablation explicitly manifested by the patient.
• Age >=18 years and written informed consent.

Exclusion Criteria:

• AF with a reversible cause.
• Previous pulmonary veins isolation or left atrial linear ablation.
• Cardiac surgery, acute coronary syndrome, percutaneous coronary intervention o ischaemic stroke <1 month before ablation.
• Intracranial haemorrhage <3 months before ablation.
• Ablation contraindicated due to 1)absolute contraindication for oral anticoagulants, 2)persistent atrial thrombus, 3)pregnancy, 4)extreme fragility and 5)life expectancy <1 year.