Restoring Sinus Rhythm Using Dual-Shock Technique in Patients With Atrial Fibrillation

The goal of this clinical trial is to assess the efficacy and acute safety of the dual electrical cardioversion (ECV) technique compared with the conventional ECV in patients with persistent atrial fibrillation. The main question it aims to answer are: * Is dual ECV more effective than conventional ECV to achieve sinus rhythm restoration? * Is dual ECV safe compared with conventional ECV? * Which are the main factors associated with cardioversion success? Researchers will compare a dual ECV technique with 400J with dual ECV with 200J and conventional ECV. Participants will be randomized to one ECV configuration. The primary efficacy endpoint will be considered the percentage of patients with successful cardioversion with the first shock. The coprimary safety endpoint will be the occurrence of adverse events during ECV.

Inclusion Criteria: * Diagnosis of persistent AF. * Effective anticoagulation for at least 3 weeks prior to the procedure or exclusion of intra-atrial thrombus by transesophageal echocardiography within the last 24 hours. * Informed consent obtained. Exclusion Criteria: * Long-standing persistent atrial fibrillation (more than 1 year of uninterrupted AF rhythm). * Emergency indication (hemodynamic instability). * Cardiac defibrillation following catheter ablation procedures. Cardiac defibrillation performed during the same procedure will be permitted if it is carried out prior to ablation. * Pregnancy. * Age \