Unifocal Right-Sided Ablation Treatment for Neurally Mediated Syncope and Functional Sinus Node Dysfunction Under Computed Tomographic Guidance

Background: Biatrial, extensive, and complex ablation strategies have been published for the treatment of neurally mediated syncope, sinus node dysfunction, and functional atrioventricular block. We have developed a less extensive and more specific approach compared with previously published cardioneuroablation strategies, called cardio-neuromodulation. It is based on tailored vagolysis of the sinoatrial node through partial ablation of the anterior right-ganglionated plexus, preferentially through a right-sided approach. Methods: Patients with syncope were enrolled between December 2016 and December 2017. They were assigned to group A if they had a positive head-up tilt test and to group B if they presented with a pause ≥3 seconds. The area to target during cardio-neuromodulation was designed offline on a computed tomographic scan. Slow heart rates and pauses were compared during 24-hour rhythm registration at baseline, at 1-month follow-up, and 6-month follow-up. Syncope burden was assessed before the procedure and at 3- and 6-month follow-up. Results: Twenty patients underwent cardio-neuromodulation through a right-sided approach (12 in group A, 8 in group B). The first application of radiofrequency energy led to a P-P interval shortening >120 ms in all 20 patients. After a mean±SD ablation time of 7±4 minutes and mean ablated surface area of 11±6 mm2, the P-P interval shortened by 219±160 ms (P<0.001). The number of beats <50/min during 24-hour rhythm registration was reduced by a median of 100% at 6-month follow-up (P<0.001). Syncope burden was reduced by 95% at 6-month follow-up (P<0.001). Conclusions: These data indicate that cardio-neuromodulation, through a right-sided and computed tomographic–guided procedure, is safe, fast, and highly reproducible in preventing inappropriate functional sinus bradycardia and syncope recurrence.