Durable Physiological Changes and Decreased Syncope Burden 12 Months After Unifocal Right-Sided Ablation Under Computed Tomographic Guidance in Patients with Neurally Mediated syncope or Functional Sinus Node Dysfunction.

Background - Cardio-neuromodulation (CardNM) is a cardioneuroablative approach aiming to create adequate vagolysis of the sinoatrial node through partial ablation of the anterior right ganglionated plexus. Methods - We performed an interventional study in patients with recurrent neurally mediated syncope (group A) or functional sinus node (SN) dysfunction (group B). Syncope burden, electrocardiogram, 24-h rhythm data, tilt table test, exercise test, and pharmacological challenge with atropine were assessed at baseline and at regular intervals to 12-months. Results - Fifty patients (31 in group A, 19 in group B) underwent CardNM. Mean number of syncopes during the previous 12 months was 9.7±18.2. The procedure was associated with a lower rate of syncope (-95%) and presyncope (-95%) at 12 months versus baseline ( P <0.001). Thirty-seven patients remained entirely free of syncope at 12 months, and the syncope-free survival curve remained stable between 12- and 30-month follow-up. After a mean ablation time of 8±4 min, P-P interval shortened by 247±146 ms ( P <0.001). Basal heart rate (HR) increased by 18% ( P <0.001) and remained stable between 6 and 12 months. At 12 months, mean HR increased by 12% in the entire cohort ( P <0.001), reached 23% in patients with baseline mean HR <70 bpm ( P <0.01), and did not increase in patients with baseline HR >70 bpm. Maximum HR during exercise decreased by 10 bpm at 1 month ( P <0.001) and was restored at 12 months. Conclusions - CardNM is a safe and fast treatment giving rise to a long-term partial SN vagolysis with no apparent short- or long-term safety concerns or undesirable persisting modifications of the intracardiac autonomous nervous system. The impact on vasoplegia is less clear. CardNM is associated with a good clinical outcome in most patients with neurally mediated syncope or functional SN dysfunction. These promising data require confirmation in a multicenter randomized trial.