Atrial Fibrillation and the Autonomic Nervous System

Catheter ablation of atrial fibrillation (AF) has been increasingly employed as a therapeutic modality to maintain sinus rhythm. However, the procedure is potentially associated with major complications and its long-term efficacy is relatively poor. Thus, the quest for additional non-pharmacological, non-ablative therapies for the management of patients with AF continues. Present methodology for catheter ablation of AF includes pulmonary vein isolation by applying radiofrequency current around the pulmonary vein ostia, in order to prevent the ectopic activity arising from the pulmonary veins from reaching the atria and thereby inducing AF. However, this approach failed to answer the fundamental question of how the generally short episodes of focal firing in the pulmonary veins are converted into AF. Experimental work has provided many lines of evidence linking the intrinsic cardiac autonomic nervous system with focal firing from the pulmonary veins via activation of the ganglionated plexi (GP) adjacent to these veins. Autonomic denervation is common following pulmonary vein isolation and has been associated with decreased risk of AF recurrence. Recent clinical studies where GP ablation was performed either in addition to the standard procedure of pulmonary vein isolation, or as a stand-alone procedure support these experimental data. These intriguing new concepts and data linking the autonomic nervous system to AF will herein be briefly reviewed.