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.