Cardioneuroablation guided by extracardiac vagal stimulation for cardioinhibitory vasovagal syncope

Abstract

Abstract Introduction Vasovagal Syncope (VVS) is often linked to abnormal autonomic reflexes, with hypervagotonia identified as a key mechanism, especially in cases with pronounced cardioinhibition. Cardioneuroablation (CNA), which involves radiofrequency ablation of cardiac vagal ganglia, targets parasympathetic hyperactivity, offering a promising treatment for recurrent VVS. This study evaluates the effectiveness and safety of anatomically guided CNA, which may provide an alternative treatment option to pacemaker implantation for younger patients with severe cardioinhibitory VVS. Methods Consecutive patients between January 2019 and October 2023 who underwent CNA at two cardiology centers were enrolled. All patients had a history of recurrent syncope, predominantly cardioinhibitory and unresponsive to conventional treatments. Patients showed no signs of conduction system disease, evidenced by normal rate responses in treadmill stress tests and 24-hour Holter monitoring. Electroanatomic mapping of the left atrium and pulmonary veins was performed. Extracardiac vagal stimulation (ECVS) through the right internal jugular vein, with or without atrial pacing, was utilized to assess baseline responses of the sinus and atrioventricular (AV) nodes. The ablation strategy was tailored based on rhythm disturbances triggered by ECVS, using sequential and anatomically guided ablation of ganglionated parasympathetic plexuses. Radiofrequency ablation, conducted with an irrigated catheter, was guided by the ablation index. Acute success was defined as the absence or significant reduction of cardiac parasympathetic response to ECVS, indicated by the elimination of asystole, severe bradycardia, or AV block. The primary endpoint was syncope recurrence during follow-up. Results The study included 25 patients (16 males; mean age 36 ± 12 years). All had documented cardioinhibition, identified through ECG monitoring (N=12), implantable loop recorders (N=5), or head-up tilt tests (N=8). The average number of syncopal episodes per patient in the year preceding ablation was 2.7, ranging from 1 to 10. Ablation was acutely successful in all cases. Post-ablation, there were no immediate complications related to the procedure, except for one convulsion deemed unrelated. Over a mean follow-up of 17 ± 14 months, 23 patients remained syncope-free. Two patients experienced syncope recurrence; despite undergoing a repeat ablation, they eventually required pacemaker implantation. Conclusion The results of this study suggest that CNA guided by ECVS, may offer a promising treatment for patients with refractory cardioinhibitory VVS. While the procedure showed a high rate of acute success and a notable reduction in syncope recurrence, further research is warranted to fully establish its role as an alternative to pacemaker implantation.