Atrial conduction changes following cardioneuroablation: insights from electrocardiographic imaging

Abstract Background Cardioneuroablation (CNA) has emerged as a therapeutic option for patients with vagally mediated bradycardias, aiming to reduce frequency of syncope episodes without pacemaker implantation. However, concerns remain regarding the potential alteration of atrial conduction and the subsequent pro-arrhythmia. Purpose We sought to investigate the impact of CNA on total atrial activation time (TAT) and atrial mean conduction velocity (CV) in a prospective cohort of patients, using electrocardiographic imaging (ECGi) to non-invasively assess global and regional atrial changes pre- and post-ablation. Methods We prospectively studied 5 patients (mean age at time of procedure 43.6 ± 21.8 years, 60% males) with vagally mediated bradycardia (both sinus pause and atrioventricular block), who underwent CNA between 2022-24. ECGi was performed for all patients prior to and after ablation. We measured TAT and mean CV, both globally and for each of 20 atrial regions (6 in the right atrium and 14 in the left atrium), before and after ablation. We then compared pre- and post-ablation measurements using paired t-tests. Results A biatrial approach for ablation was performed and all patients were successfully denervated and confirmed by a negative atropine test post-ablation. Mean radiofrequency time was 13.2 ± 8.0 min. The mean number of syncope episodes decreased from 6.8 ± 3.1 in the last 12 months before the ablation to 1.6 ± 2.3 in the 12 months following the ablation. TAT increased from 70.9 ± 5.6 ms pre-ablation to 81.2 ± 7.8 ms post-ablation (p=0.007). Mean CV decreased from 148.8 ± 5.0 cm/s to 140.7 ± 7.3 cm/s (p=0.004). The same results were found when analysing the right atrium alone, with an increase in TAT from 63.9 ± 3.7 ms to 73.5 ± 4.0 ms (p=0.001) and a decrease in mean CV from 152.3 ± 8.2 cm/s to 142.1 ± 8.6 cm/s (p=0.003). In the left atrium, we found an increase in TAT from 70.2 ± 5.8 ms to 81.1 ± 7.8 ms (p=0.007), without a significative decrease in mean CV, from 145.0 ± 9.0 cm/s to 136.1 ± 15.3 cm/s (p=0.8). No significative differences were found in conduction velocity of each atrial region pre- and post-ablation suggesting a sympathetic mechanism for CV decrease rather than a local radiofrequency effect on the tissue. Conclusions Our findings suggest that CNA is effective in reducing syncope episodes, but the increase in atrial activation time and decrease in conduction velocity may indicate a potential detrimental effect. Rigorous patient selection is therefore essential before performing the procedure.TAT and CV pre- and post-ablation ECGi pre- and post-ablation