Long-Term Evaluation of the Vagal Denervation by Cardioneuroablation Using Holter and Heart Rate Variability

Abstract

Background - Several disorders present reflex or persistent increase in vagal tone that may cause refractory symptoms even in a normal heart patient. Cardioneuroablation (CNA), the vagal denervation by RF ablation of the neuromyocardial interface, was developed to treat these conditions without pacemaker implantation. A theoretical limitation could be the reinnervation, that naturally grows in the first year, that could recover the vagal hyperactivity. This study aims to verify the vagal denervation degree in the chronic phase after CNA. Additionally, it intends to investigate the arrhythmias behavior after CNA. Methods - prospective longitudinal study with intra-patient comparison of 83 very symptomatic cases without significant cardiopathy, submitted to CNA, 49(59%) male, 47.3±17 years-old, having vagal paroxysmal atrial fibrillation 58(70%) or neurocardiogenic syncope 25(30%), NYHA Class < II and absence of significant comorbidities. CNA was performed in both atria by interatrial septum puncture, with irrigated conventional catheter and electroanatomic reconstruction. Ablation targeted the neuromiocardial interface by fragmentation mapping (AF-Nests) using the Velocity Fractionation software, conventional recording and anatomical localization of the ganglionated plexi. There were compared the time and frequency domain of the heart rate variability (HRV) and arrhythmias in 24h Holter pre-, 1-year-post- and 2-year-post-CNA. Clinical outpatient follow-up and serial Holter showed 80% asymptomatic cases at 40 months. Results - Time and frequency domain HRV demonstrated significant decrease in all autonomic parameters, showing an important parasympathetic and sympathetic activity reduction at 2 years-post-CNA (p<0.001). There was no difference in HRV between the 1-year- and 2-post-CNA (p>0.05) suggesting that the reinnervation has halted. There was also an important reduction in all brady- and tachyarrhythmias pre- vs. post-CNA, (p <0.01). Conclusions - There is an important and significant vagal and sympathetic denervation after 2 years of CNA with a significant reduction in brady and tachyarrhythmia in the whole group. There were no complications.

QTc shortening effect of ganglionated plexi ablation

“…As supporting evidence of our sympathetic denervation hypothesis, by using the heart rate variability in the 24‐h Holter, Pachon et al 15 demonstrated a significant and durable decrease in the high‐frequency (HF) band indicating sympathetic tone. In their work, although they detected a shortening trend on QTc levels, it was not statistically significant 15 . However, PVI in addition to GP ablation was performed in 70% of cases.…”

Molecular Insights in Atrial Fibrillation Pathogenesis and Therapeutics: A Narrative Review

“…Various methods of cardiac ANS assessment (heart rate variability, [ 82 , 83 ] skin sympathetic nerve activity [ 84 ], metaiodobenzylguanidine (MIBG) scintigraphy [ 85 ]) imply that ANS instability is implicated in human AF pathogenesis.…”

Electrocardiographic Patterns in Patients with Neurally Mediated Syncope

“…Heart rate variability has been evaluated in patients with NMS as a surrogate for reinnervation after cardioneuroablation (CNA). Pachon and colleagues [ 37 ] found that minimum and mean HR increased significantly at two years after CNA, but between the first and the second years, there were no essential changes, emphasizing the idea that no reinnervation occurred [ 38 ]. In addition, CNA eliminates the CI reflex and keeps most patients asymptomatic, maintaining exercise tolerance and also preventing pacemaker implantation [ 39 ].…”

“…In addition, CNA eliminates the CI reflex and keeps most patients asymptomatic, maintaining exercise tolerance and also preventing pacemaker implantation [ 39 ]. This result is offering an encouraging treatment option for patients with NMS [ 37 , 40 , 41 ].…”