Table 1 Eligibility criteria in Catheter Ablation versus Thoracoscopic Surgical Ablation in Long Standing Persistent Atrial Fibrillation trial

Inclusion criteria

 Age ≥ 18 years

 Long-standing persistent AF (> 12 months’ duration)

 EHRA symptom score > 2 (see Additional file 1)

 Left ventricular ejection fraction ≥ 40%

 Suitable for either ablation procedure

Exclusion criteria

 Valvular heart disease with severity greater than mild

 Contraindication to anticoagulation

 Thrombus in the left atrium despite anticoagulation in therapeutic range

 Cerebrovascular accident within the previous 6 months

 Previous thoracic or cardiac surgery (including surgical interventions for AF)

 Prior left atrial catheter ablation for AF

 Unable to provide informed written consent

 Active malignancy, another severe concomitant condition or presence of implanted cardiac devices that would preclude patient undergoing study-specific procedures

 Pregnant or breastfeeding, or women of childbearing age not using a reliable contraceptive method