Importance of bilateral vagus nerve stimulation for effective atrioventricular node denervation during cardioneuroablation

Abstract

Background The progression of parasympathetic denervation of the atrioventricular node (AVN) during cardioneuroablation (CNA) can be evaluated by extracardiac vagal stimulation (ECVS). The right vagus nerve is usually used for stimulation (R-ECVS) because the right jugular vein is easily accessible. However, the AVN node is predominantly under the control of the left vagus nerve. Purpose To highlight the importance of left vagus stimulation (L-ECVS) for effective AVN denervation. Methods Both R-ECVS and L-ECVS (frequency: 50 Hz; pulse width: 0.05 ms; output 1 V / 1 kg; max. 70 V, duration 5 s) was attempted in 80 patients (age: 41±12 years, 45% men) undergoing CNA with stepwise strategy consisting of ablation of right anterior ganglionated plexus (RAGP) followed by ablation of posteromedial left ganglionated plexus (PMLGP). The study objective was the AVN response to L-ECVS (evaluated as the max. R-R interval during stimulation train) at the point when AVN non-reactivity to R-ECVS was achieved. Results A total of 59 patients were suitable for the analysis. Of the remaining 21 patients, left (n=14) or right (n=2) jugular veins were not accessible, AVN non-reactivity to L-ECVS was achieved before non-reactivity to R-ECVS (n=4), or AVN denervation was not achieved at all (n=1). At baseline, the AVN response was identical for R-ECVS (max. R-R median: 6.9 s, interquartile range [IQR]: 5.7–8.2 s) and L-ECVS (median: 7.1 s, IQR: 6.0–8.3 s), P=0.44. AVN non-reactivity to R-ECVS was present already at baseline (n=2); was achieved after ablation of RAGP (n=14), after ablation PMLGP (n=38), or after extensive ablation (n=5). At the point of AVN non-reactivity to R-ECVS, the response of AVN to L-ECVS was as follows: none (n=25), 2: 1 AV block (n=13) or complete AV block (n=21). The corresponding median of max. R-R interval was: 1.2 s, IQR: 0.6–4.8 s distributed as shown in Figure 1. Conclusions In 34/59 (58%) patients, significant AVN response to L-ECVS persists after reaching AVN non-reactivity to R-ECVS. Stimulation of both vagal nerves tightens the procedural endpoint and may increase the clinical efficacy of CNA, especially in patients with dominant AVN disorder. Funding Acknowledgement Type of funding sources: None.

Clinical controversy: methodology and indications of cardioneuroablation for reflex syncope

“…The post-ablation absence of provoked vagal responses of sinus and AV nodes is a highly sensitive and specific measure of their denervation. 12 However, the utility of extracardiac vagus nerve stimulation for guiding the CNA has not been formally investigated in CNA studies with clinical endpoints.…”

Advantages and pitfalls of selective cardioneuroablation targeting the atrioventricular node

“…Although standalone ablation of the superior right ganglionated plexus (GP) (SRGP) has a significant impact on the AV node, complete AV nodal denervation in many patients is only achievable by additional ablation of the posteromedial left GP (PMLGP). 2 Nevertheless, SRGP ablation alone can be clinically successful, even with ablation limited to the right atrial aspect of the superior interatrial septum, as we demonstrated previously. 3 …”

Do we have a clear end‐point for cardioneuroablation?

“…Our experience suggests that there may be a difference between the right and left vagal nerve input. 26,27 Therefore, it is important stimulating vagal nerves on both sides to ensure complete vagal denervation.…”

“…The procedure has to be performed in general anesthesia since high frequency stimulation is painful and results in muscular contractions. Our experience suggests that there may be a difference between the right and left vagal nerve input 26,27 . Therefore, it is important stimulating vagal nerves on both sides to ensure complete vagal denervation.…”