Does Vagal Response Indicate Cardiac Autonomic Modulation and Improve the Therapeutic Effect of Pulmonary Vein Isolation in Patients With Paroxysmal Atrial Fibrillation? Insides From Cryoballoon Ablation

An interplay between left atrial (LA) ganglionated plexi (GP), a part of the intrinsic cardiac autonomic nervous system (CANS), and pulmonary veins (PVs) is considered to be an important mechanism related with the initiation and maintenance of atrial fibrillation (AF). Therefore additional GP ablation has been reported with better ablation outcomes when added to RF-based PV isolation (PVI). A cryoballoon ablation (CBA) is an anatomically based approach which allows PVI that is highly safe and efficacious. The extension of the scar created by the cryoballoon frequently extends beyond the PV orifice in the acute and chronic post-ablation phase creating a set of lesions that are near the LA-GP area and inadvertent damage. A marked vagal response (VR) observed during CBA is considered a marker for the CANS modification. However, changes in the autonomic tone were independently noted from the presence of VR in several studies. Moreover, it is not clear if these changes are transient or long-lasting, and it has been shown that the presence of VR increases ablation success although with conflicting results. In previous studies assessing the influence of CBA on the autonomic balance, CANS modulation was appraised with different surrogates, a small number of individuals were usually recruited and both paroxysmal and persistent AF populations were included. Therefore, the investigators sought to evaluate the incidence of VR observed during CBA-based PVI, its impact on CANS assessed with widely accepted heart rate variability (HRV) analysis, and in relation to ablation outcomes in a large paroxysmal AF (PAF) cohort.