RADIOFREQUENCY CATHETER DENERVATION OF SINUS NODE BY TARGETTING THE RIGHT ANTERIOR GANGLIONATED PLEXUS: TOWARDS MINIMIZING THE LESIONS SET

Background: Radiofrequency catheter (RF) ablation of the superior ganglionated plexus (RAGP) that modifies parasympathetic innervation of the sinus node (SAN) is used for the treatment of functional bradyarrhythmias. The RAGP is usually targeted from the endocardial aspect of both the right and left atria.
Objective: To investigate the acute effect of a minimized biatrial set of ablation lesions aimed at denervating the SAN.
Methods: In patients with cardioinhibitory reflex syncope (n=25) or symptomatic functional sinus bradycardia (n=7), a minimum of 2x2 and a maximum of 2x3 RF lesions (at the discretion of the operator) were created from both sides of the superior interatrial septum with a setting of 30 W / 30 s and strictly contralateral configuration. The response to extracardiac vagus nerve stimulation (ECVS) was assessed before and after ablation. This response was quantified by the ratio of the maximum induced P-P interval and the cycle length of the current sinus rhythm (MaxPPratio).
Results: In 32 patients (41±13 years, 56% men), ablation of RAGP (2x3 and 2x2 lesions in 23 and 9 patients, respectively) resulted in attenuation of the response to ECVS from 7.9±3.5 s to 0.9±0.2 s (Figure, left panel). After ablation, only 9 patients had MaxPPratio >1.1 and none of the patients had MaxPPratio >1.6 (Figure, right panel). In 6 patients with MaxPPratio >1.3, the extension of original lesions easily suppressed the residual responsiveness of SAN to ECVS.
Conclusion: Biatrial RAGP ablation with a total RF time of 2-3 minutes resulted acutely in virtually complete SAN denervation in 72% of patients. Highly significant, but incomplete SAN denervation in remaining patients was successfully treated by extension of original ablation clusters. The long-term durability of SAN denervation associated with this ablation strategy remains to be investigated.