RF ablation is a standard practice approach for the symptomatic AF. The interest of substrate ablation, completing pulmonary vein isolation is controversial. The current ablation strategy for persistent AF ablation is a step-by step guided approach: PVI is most often followed by a large ablation of fragmented electrograms identified in AF or completed by linear ablation, but this current ablation strategies have shown a limited success rate with frequent arrhythmia recurrences. Recent studies suggest that the atrial arrhythmogenic sites are related to regions with heterogeneities and increased fibrosis, which is detected by reduced bipolar voltage areas.

Defragmentation low voltage areas (LVA) in sinus rhythm (SR) in addition to PVI may represent an efficient strategy for the ablation of persistent AF.

This is a prospective multicentric interventional study in France. Inclusion criteria: minimum age 18 years, patients with persistent AF ablation, no specific indication restrictions or equipment used regardless of the outcome of the procedure. Number of patients: 210 patients included in 9 centres. Three groups will be constituted: Group 1: PVI without LVA identified, group 2: PVI only, with LVA identified but defragmentation will not be carried out and group 3: PVI with LVA identified and defragmentation will be carried out. Definition of LVA in SR: all potentials<1mV, fragmented signal: more than 5 deflexions, duration>55ms. Inducibility of AF is realised at the end of the procedure. Usual blanking period of 3 months. Follow-up: clinical evaluation, ECG, and 24h-holter ECG at 6, 12 and 18 months.

Primary outcome: recurrence of AF at 18 months. Secondary outcomes: comparison of efficiency and safety of the procedures, procedural data (X-ray data, RF duration, AF inducibility), organised atrial tachycaria occurring during FU.