This is a prospective, randomized (1:1), pilot study enrolling 200 patients with symptomatic atrial fibrillation or atrial tachycardia (AF/AT) recurrence requiring repeat ablation following a single prior PVI procedure for AF.

Inclusion Criteria:

• Patients with symptomatic non-valvular AF or AT recurrences despite of one previous PVI (+/- cavotricuspid isthmus ablation) catheter ablation for AF.

Age 18-85 years Willing and able to comply with the study protocol Willing and able to operate a device for rhythm monitoring

Exclusion Criteria:

• Patients with contraindications to catheter ablation or inability to provide informed consent Patients who underwent PVI + (ablation of additional RA/LA substrates/areas) Patients who did not undergo PVI before Patients who underwent more than one prior PVI/Re-PVI Patients with left atrial size > 55mm Patients with longstanding persistent AF > 12 months duration Prior surgical AF ablation Contraindications for repeat ablation Prior implantable loop recorder History of mitral valve surgery Severe mitral valve regurgitation Inability to be treated with oral anticoagulation Presence of intracardiac thrombi Chronic obstructive pulmonary disease or Asthma treated with long acting bronchodilatators Obstructive sleep apnea syndrome requiring CPAP mask ventilation Pregnancy Participation in other clinical studies Unwilling to follow the study protocol and to attend follow-up visits