Integrity of the Ganglionated Plexi Is Essential to Parasympathetic Innervation of the Atrioventricular Node by the Right Vagus Nerve
The influence of vagal tone on the electrophysiological properties of the atrioventricular node (AVN) has been well documented. However, the integral links between the AVN and cardiac vagal stimulation remain poorly understood in humans. Several studies in animals, including the work conducted by Hou et al.,1 have demonstrated that the vagus nerve exerts its influence on the AVN through the epicardial fat pads that are primarily located on the posterior wall of the left atrium. These fat pads contain ganglionated plexi (GP), which are located close to the antral area of the pulmonary veins.2 These regions are ablated during epicardial pulmonary vein isolation for the treatment of atrial fibrillation (AF). A number of studies have reported that pulmonary vein isolation for the treatment of AF may be accompanied by transient sinus bradycardia or AVN block, suggesting that radiofrequency (RF) ablation affects vagal cardiac control in humans.3 However, the importance of the fat pads in the vagal innervations of human AVN is not clear. The present study aimed to understand whether fat pad ablation suppresses the vagal effects of the right vagus nerve (RVN) on the AVN based on selective high‐frequency stimulation (HFS)6 of the RVN and GP in a right monolateral thoracoscopic epicardial ablation for the treatment of AF. Our hypothesis was that fat pad ablation will prevent the effect of HFS of the RVN on the AVN conduction properties, thereby demonstrating the importance of these structures in the vagal control of the AVN.