Catheter Ablation for Persistent Atrial Fibrillation: a Multicentre Randomised Trial of Pulmonary Vein Isolation (PVI) versus PVI with Posterior Left Atrial Wall Isolation (PWI) - the CAPLA Study: CAPLA: randomised trial for persistent AF.

Abstract Background : The success of pulmonary vein isolation (PVI) is reduced in persistent AF (PsAF) compared to paroxysmal AF. Adjunctive ablation strategies have failed to show consistent incremental benefit over PVI alone in randomised studies. The left atrial posterior wall is a potential source of non-PV triggers and atrial substrate which may promote the initiation and maintenance of PsAF. Adding posterior wall isolation (PWI) to PVI had shown conflicting outcomes, with earlier studies confounded by methodological limitations. Objectives : To determine whether combining PWI with PVI significantly improves freedom from AF recurrence, compared to PVI alone, in patients with PsAF. Methods : This is a multi-centre, prospective, international randomised clinical trial. 338 patients with symptomatic PsAF refractory to anti-arrhythmic therapy (AAD) will be randomised to either PVI alone or PVI with PWI in a 1:1 ratio. PVI involves wide antral circumferential pulmonary vein (PV) isolation, utilising contact force sensing ablation catheters. PWI involves the creation of a floor line connecting the inferior aspect of the PVs, and a roof line connecting the superior aspect of the PVs. Follow up is for a minimum of 12 months with rhythm monitoring via implantable cardiac device/ loop monitor, or frequent intermittent monitoring with an ECG device. The primary outcome is freedom from any documented atrial arrhythmia of > 30 seconds off AAD at 12 months, after a single ablation procedure. Conclusion : This randomised study aims to determine the success and safety of adjunctive PWI to PVI in patients with persistent AF.