Inclusion Criteria:  Age > 18 years old Signed informed consent. Scheduled to undergo a clinically indicated, first-time catheter ablation procedure for the treatment of persistent atrial fibrillation. In atrial fibrillation at the time of the index procedure.  Exclusion Criteria:  Paroxysmal atrial fibrillation. Previous ablation procedure for atrial fibrillation. Left ventricular ejection fraction < 45% Obesity with BMI > 35 kg/m2 Congenital heart disease. Previous cardiac surgery with atriotomy. Previous left atrial appendage closure/ligation. Contraindications to systemic anticoagulation, catheter ablation, and/or general anaesthesia. Pregnancy Current enrolment in a study evaluating another device or drug.