Inadvertent neuromodulation during pulmonary vein isolation for atrial fibrillation – immediate and short-term effects of radiofrequency and cryogenic energy

Abstract

Inadvertent vagal denervation has been reported as an adjunctive effect during pulmonary vein isolation (PVI) for atrial fibrillation (AF). However, it is not known how frequent and durable this effect is during thermal ablation. Material and methods: This is a retrospective study of consecutive patients with AF and first PVI in sinus rhythm using radiofrequency or cryogenic energy. We studied the incidence of non-targeted and non-transient heart rate (HR) acceleration, induction and abolition of vagal reflex (VR), as well as the durability of the HR increase at the end of the first month. Results: PVI was carried out in 102 patients (cryo, n = 46). Overall, 60 patients (58.8%) had inadvertent neuromodulation, presented by VR induction and abolition (n = 18, 17.6%) and predominantly by HR increase (n = 50, 49%). In patients with vs those without HR acceleration the mean HR increase at the end of the procedure was 14.2 ± 5.64 bpm vs. -2.63 ± 5.43 bpm, and at the next day – 10.6 ± 7.53 bpm vs. 3.68 ± 7.75 bpm (p < 0.001 for all). The mean HR at 1 month was 74.2 ± 9.91 bpm vs. 68.9 ± 12 bpm (p = 0.048). Patients with a durable HR increase were younger (median age 61 vs. 65.5 years, p = 0.016) and less frequently had heart failure with reduced ejection fraction (1% vs. 6.9%, p = 0.031). Conclusion: Inadvertent neu-romodulation occurs in more than half of the patients with radiofrequency or cryo PVI for AF. It is mostly represented by a HR increase and persists for up to at least one month post-procedurally.