This study will be a multicenter, open, prospective, randomized trial. Patients with either paroxysmal or persistent atrial fibrillation will be considered for the study. (For US, only paroxysmal atrial fibrillation will be considered.) Eligible subjects will be randomized into one of two arms in the study: (1) targeted CFAE ablation or (2) generalized CFAE ablation. Both techniques will then be followed by PVAI (pulmonary vein antral isolation) as part of a hybrid ablation strategy. The nature of the ablation procedures does not allow physicians to be blinded to the randomization.