Currently available antiarrhythmic drugs for the treatment of atrial fibrillation (AF) have a limited efficacy and often cause long-term side effects. Pulmonary vein isolation is the therapy of choice in drug-refractory patients. Recent studies have shown that ablation have a greater efficacy in patients in whom AF is maintained hierarchically and after ablation of rotors. The non-invasive identification of specific mechanism of AF maintenance in each patient could allow the selection of the most appropriate treatment.

The MAIN GOAL of this project is to clinically validate the technology for the noninvasive identification of the mechanisms responsible for maintenance of AF by body surface electrical mapping. To achieve this goal, noninvasive mapping of the atrial activity will be correlated with simultaneous endocardial mapping (high density contact catheters) using advanced signal analyses techniques (Dominant frequency, phase and causality mapping, inverse solution problem). These analyses will be performed in patients with different mechanisms of maintenance of AF (e.g. paroxysmal, persistent, valvular) undergoing AF ablation for clinical indication. Both endocardial and body surface mapping results will be correlated with biomarkers levels, MRI scans and AF outcomes of AF ablation at 6 months and 1 year after the procedure.

Wide antrum circumferential pulmonary vein isolation with demonstration of bidirectional block will be performed using standard cooled-tip radiofrequency catheters. In patients with mitral stenosis, PBMV will be performed according to Inoue´s technique followed by wide antrum circumferential pulmonary vein isolation. In all patients, MRI/CT scans and fibrosis biomarkers will be obtained at baseline, 6 months and 1 year post ablation.

Inclusion Criteria:

• Patients with paroxysmal AF symptomatic and refractory to at least one antiarrhythmic medication.
• Patients with persistent AF symptomatic and refractory to at least one antiarrhythmic medication.
• Patients with severe mitral stenosis (mitral valve area ≤1.5 cm2, stage D) and favorable valve morphology in the absence of left atrial thrombus or moderate-to-severe mitral regurgitation.
• Patients must be able and willing to provide written informed consent to participate in the study.
• Prior anticoagulation for> 4 weeks or transesophageal echocardiogram excluding intracardiac thrombi (in patients with paroxysmal AF).

Exclusion Criteria:

• Patients with inadequate anticoagulation levels.
• Patients with left atrial thrombus, tumor, or another abnormality which precludes catheter introduction on TEE prior to the procedure.
• Patients with moderate-to-severe mitral regurgitation.
• Patients with contraindications to systemic anticoagulation with heparin or coumadin.
• Prior atrial fibrillation ablation.
• Patients who are or may potentially be pregnant.
• Contraindication for adenosine administration;
• Current enrollment in another investigational drug or device study.
• Pacemaker or Implantable Cardioverter Defibrillator.

AF patients with different mechanisms of maintenance (i.e. paroxysmal, persistent, valvular) and clinical indication for AF ablation.