Inclusion Criteria:  Symptomatic non-valvular atrial fibrillation with no prior ablation with an indication for re-ablation according to current guidelines. Age 18-85 years. Patient is able to provide informed consent and is willing to comply with the study protocol.  Exclusion Criteria:  Contraindications for left atrial ablation History of interventional or surgical AF-ablation History of stroke during the past 12 months BMI >40kg/m2 History of mitral valve surgery Severe mitral valve regurgitation Inability to be treated with oral anticoagulation Presence of intracardiac thrombi Contraindication or absolute indication for one of the two strategies Pregnancy Participation in other clinical studies Unwilling to follow the study protocol and to attend follow-up visits