Age-related differences in efficacy of cardioneuroablation in patients with functional bradyarrhythmias

Abstract Introduction Cardioneuroablation (CNA) has been increasingly used to treat various forms of symptomatic functional bradyarrhythmias. The guidelines recommend pacemaker implantation in patients aged > 40 years, however, optimal age cut-off for CNA has not been established. Aim To assess efficacy of CNA in different age-groups of patients with symptomatic functional bradyarrhythmias. Methods The study group consisted of 248 consecutive patients (137 females, 111 males, mean age 39.6±14, range 17-73 years) who underwent CNA for very symptomatic vaso-vagal reflex (VVR) (n=193), functional sinus bradycardia (FSB) (n=31) or functional atrio-ventricular block (FAVB) (n=24). All patients had ineffective previous non-pharmacological therapy and positive response to atropine (>25% increase in sinus rate and regression of AVB with no PR prolongation in the AVB group). The bi-atrial procedure was performed under general anaesthesia and muscle relaxation using anatomical approach (3-D electro-anatomical mapping and intracardiac echocardiography). Intraprocedural efficacy was assessed using extracardiac vagal stimulation (ECVS). Efficacy of CNA was defined as no recurrence of symptoms during at least one-year follow-up. Results All patients had uneventful procedure with ECVS documenting complete vagal denervation. During a median follow-up of 26 months (range 12-87 months) 200 (81%) patients remained free from symptom recurrence. The highest efficacy of CNA was observed in the VVR group (159 (82%)), followed by FSB group (24 (77%)) and FAVB group (17 (71%)) (NS). Efficacy of CNA was similar in patients aged <40 vs ≥40 years (27 (79%)) vs 101 (83%), NS) and when the cut-off value was set at 50 years (153 (83%) vs 47 (75%), NS). However, when patients aged <60 years and ≥60 years were compared, significantly higher efficacy was seen in the younger group (189 (83%) vs 11 (58%), p=0.009). The subgroup analysis (VVT, FSB, and FAVB) showed similar results. Other baseline demographic and clinical parameters as well as sinus rate changes following baseline and post-procedural atropine did not significantly differ between responders and non-responders. During follow-up, 7 patients received pacemaker because CNA was ineffective. All these patients were aged > 50 (range 55-73 years). Conclusion Cardioneuroablation should not be confined only to young people, however, in those aged > 60 years the procedure is significantly less effective and permanent pacing is frequently needed. The results of this analysis suggest that age cut-off for performing CNA may be set at 50 years.