In clinical studies, epicardial or endocardial partial ganglionated plexi (GP) ablation may prevent AF,1-4 and parasympathetic denervation has been proposed as a potential mechanism of circumferential or antral pulmonary vein (PV) ablation for the treatment of atrial fibrillation.5,6 However, there have also been reports of a temporary only 7 or even proarrhythmic effect of this approach by means of increased vulnerability of vagally-mediated AF,8,9 or ablation-related macro-reentrant left atrial tachycardias.10 Thus, the potential contribution of GP modification to clinical success of circumferential or antral pulmonary vein ablation that unavoidably affects adjacent GP is not known. Few publications exist on isolated GP ablation with variable results in terms of eliminating paroxysmal or persistent AF.11-13 We have recently shown that anatomically-oriented regional ablation at the areas of GP is superior to selective GP ablation, following identification of GP by high-frequency stimulation, conferring success rates comparable to these of pulmonary vein (PV) isolation procedures.13 We hypothesized that GP ablation guided by both HF stimulation and anatomical orientation is superior to PV isolation in patients with paroxysmal AF. We also aimed at comparing these two approaches with a combination of GP ablation and PV isolation. We are, therefore, conducting a randomized study comparing the three techniques in patients with drug-refractory paroxysmal AF.