The investigator propose to test the efficacy of adjunctive ET-GP ablation in patients undergoing redo PVI for paroxysmal AF.

Patients with ongoing paroxysmal arrhythmias after pulmonary vein isolation (PVI) for paroxysmal and persistent atrial fibrillation (AF) get incrementally less benefit with redo-PVI. This implies non-pulmonary vein (PV) triggers, which are more challenging to locate. The autonomic nervous system is implicated in the multifactorial pathogenesis of AF but few studies have attempted neural targeting as a therapeutic intervention. We have demonstrated that stimulation of specific left atrial ganglionated plexi (GPs) triggers both AF and atrial ectopy and importantly stimulation of these sites may not induce AV block, the 'conventional' marker used to locate GPs. Having shown that these ectopy-triggering GP (ET-GP) sites are anatomically stable and can be rendered inactive by either ablation at the site or by ablation between the site and the adjacent PV, a single centre study suggests that ET-GP ablation can prevent recurrent AF in some patients.

Inclusion Criteria:

• Males or females eighteen (18) to eighty five (85) years old
• Paroxysmal atrial fibrillation
• Previous pulmonary vein isolation
• Suitable candidate for catheter ablation
• Signed informed consent

Exclusion Criteria:

• Contraindication to catheter ablation
• Presence of a cardiac thrombus
• Valvular disease that is grade moderate or greater
• Any form of cardiomyopathy
• On amiodarone therapy
• Patients who lack capacity
• Active gastrointestinal bleeding
• Active infection or fever
• Renal failure (Creatinine >200µmol/L)
• Life expectancy shorter than the duration of the trial
• Bleeding or clotting disorders or inability to receive heparin
• Pregnant