- Patients with persistent AF must be on continuous anticoagulation with warfarin (INR 2-3) for> 4 weeks prior to ablation. In patients with paroxysmal AF no continuous anticoagulation therapy with warfarin for > 4 weeks prior to ablation will be needed provided a transesophageal echocardiogram performed prior to ablation exclude the presence of thrombi or other abnormalities that discourage performing the procedure.