The most commonly used approach to localize the major atrial GP is to apply high-frequency stimulation (HFS) to the presumed GP areas to elicit AV block. This method has low specificity and sensitivity because endocardial GP can be embedded in epicardial fat pads.106,124 Some investigators have suggested that HFS mainly reveals the afferent link of the ANS, suggesting that sites eliciting vagal responses do not coincide with sites where GP clusters and efferent autonomic nerves are located.125 Another issue is reinnervation of the ANS during follow-up.108,114 Whether reinnervation causes recurrent AF postablation remains uncertain. One study has reported that reinnervation of the ANS in patients after RF ablation is not directly related to AF recurrence.126