Cardioneuroablation for asystolic reflex syncope-left or right atrial approach? A randomized prospective Roman II study-preliminary results

FUNDING ACKNOWLEDGEMENTS: Type of funding sources: Public Institution(s). Main funding source(s): Centre of Postgraduate Medical Education BACKGROUND: Cardioneuroablation (CNA) by means of radiofrequency ablation of ganglionated plexi (GP) has emerged as a new promising therapeutic tool in patients with asystolic reflex syncope, however, optimal procedural strategy has not yet been established. PURPOSE: To compare acute efficacy of CNA using right atrial (RA) versus left atrial (LA) approach. METHODS: This prospective randomized study included 36 patients (age: 40±13 years, 14 males) who were randomized to the RA group (n=19) or LA group (n=17). Intra-procedural efficacy of CNA was measured using extracardiac vagal stimulation [(ECVS) [50 Hz, 0.05 ms, 1 V/kg (<70V), 5 s)]. If RF applications in the RA group occurred ineffective (firstly, paraseptal GPs - RAGP and PMLGP, followed by Ao-SVC GP and PMLGP from coronary sinus) there was a crossover to the LA where further applications were performed. Similarly, if RF applications in the LA group (paraseptal GPs, followed by LSGP and LIGP) did not cause complete vagal denervation on ECVS, there was a crossover to the RA. RESULTS: Both groups were comparable concerning clinical and demographic parameters. In the RA group complete vagal denervation confirmed by ECVS was achieved in 7 (37%) patients versus 14 (82%) patients from the LA group (p=0.008). Of 12 crossovers from RA to LA, 7 (58%) were due to ineffective CNA, 2 (17%) due to permanent nodal rhythm precluding accurate localization of sinus node, and 3 (25%) due to earliest sinus node activation and/or phrenic nerve course at the site of potential RF applications. In the LA group, all 3 crossovers were due to lack of complete vagal denervation on ECVS. Finally, after all crossovers, in all patients lack of response to ECVS was achieved. Procedural time (107±24 vs 106±24 min), x-ray dose (2,12±2,72 vs 2,08±2,64 Gycm2 and 17,43±20,38 vs 17,22±40,08 mGy), and electrophysiological parameters measured before and after CNA were similar in both groups. No complications were noted. CONCLUSIONS: CNA in the LA is more often associated with complete vagal denervation compared with the RA approach only. CNA performed in both atria (after crossovers) resulted in unresponsiveness to ECVS in all patients. Thus, biatrial CNA may be a preferable approach. Whether these results translate to long-term efficacy of CNA needs to be established.