Selective atrial vagal denervation guided by spectral mapping to treat advanced atrioventricular block.

Abstract

Asymptomatic nocturnal long ventricular pauses are usually detected accidentally and it has been suggested that they may lead to sudden death. Identification of predisposing factors could prevent cardiovascular events. We report the case of a patient with frequent asymptomatic nocturnal ventricular pauses of 3-11 s, characteristic of a vagally mediated atrioventricular (AV) block. Echocardiography, treadmill test, thyroid function test levels, and polysomnogram were normal. In an attempt to reduce the risk, it was decided that an atrial vagal denervation induced by radiofrequency (RF) ablation (cardioneuroablation) could be useful. Spectral mapping was used to localize endocardial vagal innervation in the right and left aspects of the inter-atrial septum, responsible for the sinus node and AV node modulation, and RF pulses were applied in those sites only. After finishing the procedure, significant changes were observed in the heart rate (66-90 b.p.m.), atrial-His interval (115-74 ms), Wenckebach cycle length (820-570 ms), and sinus node recovery time (1100-760 ms). Follow-up Holter recording demonstrated that the number of ventricular pauses had reduced from 438 to 0. Heart rate and time domain characteristics were compatible with vagal denervation. Ablation of the endocardial vagal innervation sites seems to be safe and efficient in reducing the frequency and the length of the ventricular pauses. It was possible by identifying certain spectral components of the atrial electrogram, resulting in a conservative approach.