Cardioneuroablation focused on the atrioventricular node: a comparison of right and left atrial approach

Radiofrequency catheter ablation of posteromedial left ganglionated plexus is a critical step to eliminate the vagal input to the atrioventricular node (AVN) for the treatment of symptomatic episodes of functional AV block. This ganglionated plexus can be effectively targeted from the coronary sinus (CS) or from the endocardial aspect of the right (RA) and left (LA) atria.

We investigated the effect of ablation at individual sites on the suppression of parasympathetic modulation of AVN.

The study included 20 patients (age: 42±13 years, 45% males) who underwent cardioneuroablation in general anesthesia. Posteromedial left ganglionated plexus was ablated from [1] the CS (proximal 2-cm segment), [2] the RA aspect (between the fossa ovalis and inferior vena cava), and [3] the LA aspect (middle bottom part adjacent to inferior rim of fossa ovalis). Patients were randomly (1:1) assigned to CS-to-RA or RA-to-CS ablation order. LA ablation was always the last step. The response to extracardiac vagus nerve stimulation (ECVS; 50 Hz, 0.05 ms, 1 V/kg [<70V], 5 s) while atrial pacing (100 bpm) was recorded at baseline and after each ablation step. The number of non-AV-conducted beats during the ECVS was considered a measure of AV nodal denervation. Both right and left vagus nerves were sequentially stimulated and the stronger response of the AV node was taken into account.

Temporal development of outcome measure with the progression of ablation is shown in Figure 1. CS ablation resulted in much stronger AV nodal denervation compared to RA ablation (P=0.02). However, RA ablation still provided some effect on top of CS ablation. The combination of CS + RA ablation resulted in complete AVN denervation in 8 (40%) patients. Subsequent LA ablation increased the number of denervated patients to 14 (70%). Two more patients were subsequently denervated by ablation elsewhere. In four patients, AVN denervation was not achieved but their responsiveness to ECVS was significantly suppressed compared to the baseline.

All ablation clusters targeting posteromedial ganglionated plexus convey complementary effects. Biatrial cardioneuroablation seems essential for efficacious suppression of parasympathetic modulation of AVN.

Type of funding sources: None.