The Characteristics of Vagal Response During Radiofrequency Pulmonary Vein Isolation in Paroxysmal Atrial...

Vagal response (VR) was thought to the successful rate in catheter ablation of atrial fibrillation (AF). However, little is known about VR during pulmonary vein isolation (PVI) in AF and heart failure (HF). This study aims at investigating the incidence, risk factors and clinical outcomes of VR during PVI in paroxysmal AF with HF.

A total of 551 paroxysmal AF patients were enrolled and classified according to HF status: without HF, HF with preserved, reduced and mildly reduced ejection fraction. The VR was defined as atrioventricular block, asystole or an increase in the R-R interval by 50% during ablation.

VR had the same occurrence rate between patients without HF and those with HFpEF (63 [20.5%] vs. 22 [18.9%], p = 0.722). However, VR were less frequently observed in HFmrEF and HFrEF(3 [5.0%] and 2 [2.9%], p = 0.004 and < 0.001 compared with without HF, respectively). Left ventricular EF ≥ 50% was independently associated with intraprocedural VR by multivariable analysis (p = 0.007). Patients with HFrEF or HFmrEF showed a higher mean and slower heart rate with decreased heart rate variability than those without HF. After 18.3 ± 7.4 months' follow-up, 2 of 22 (9.0%) HFpEF patients with VR and 12 of 94 (12.8%) without VR had AF recurrence (p = 0.942). Four HFrEF or HFmrEF patients with VR maintained sinus rhythm during 18.3 ± 4.9 months' follow-up.

Intraprocedural VR is not uncommon in HFpEF but is rarely observed in HFmrEF and HFrEF. Autonomic nervous system remodeling in HF, manifesting as a decrease in heart rate variability, might be the underlying reason. VR does not indicate a better clinical outcome in HFpEF.