Cardioneuroablation for Treatment of Atrioventricular Block

Abstract

Background: The contribution of autonomic influences to atrioventricular block (AVB) is unclear. Although cardioneuroablation has been used to treat cardioinhibitory vasovagal syncope, its role in treating functional paroxysmal and persistent AVB has not been formally evaluated. Methods: We used a stepwise protocol in 241 consecutive patients presenting with symptomatic AVB to identify 31 (12.9%) patients with functional or vagally mediated AVB. All patients had episode(s) of syncope in previous 12 months, and AVB was persistent in 17 (54.8%) patients. All 31 patients received targeted catheter-based cardioneuroablation, and their follow-up outcomes were evaluated with serial Holter monitoring. Results: Twenty-eight patients received biatrial or left-sided cardioneuroablation while 3 received only right-sided cardioneuroablation because of structural factors that precluded safe attempts at transseptal puncture. Procedural success, as defined as acute reversal of AVB and complete abolition of atropine response, was achieved in 30 (96.7%) cases, while the remaining patient received a pacemaker. Over a mean follow-up of 19.3±15 months, AVB episodes were observed in 2 (6.7%) of 30 cases, and 3 (9.6%) patients required pacemaker implantation during follow-up. Conclusions: Functional AVB can be identified in a minority of patients presenting with high-grade AVB. Cardioneuroablation for these patients results in encouraging medium-term outcomes.

Extracardiac Vagal Stimulation-Assisted Cardioneuroablation: Dynamically Evaluating the Impact of Sequential Ganglionated Plexus Ablation on Vagal Control of SAN and AVN in Patients with Sinoatrial Node Dysfunction

“…The sinus atrial node, phrenic nerve, coronary sinus, and His bundle were labeled. According to the studies of Pachon et al and Aksu et al, the identification of individual GPs locations was guided by the local fractionated intracardiac electrograms in the proposed anatomic distribution area in reconstructed bilateral atria [ 13 , 16 , 23 , 26 ]. The GPs were mapped and targeted in the following sequence at our center: the GP between the aortic root and the medial wall of the superior vena cava (Ao-SVC GP); the GP between the posterior wall of the coronary sinus ostium and the left atrium (PMLGP); the GP between the anterior antrum of the right superior pulmonary vein and the superior vena cava (RAGP); and the GP in the superolateral area around the root of the left superior pulmonary vein (LSGP).…”

“…The GPs were mapped and targeted in the following sequence at our center: the GP between the aortic root and the medial wall of the superior vena cava (Ao-SVC GP); the GP between the posterior wall of the coronary sinus ostium and the left atrium (PMLGP); the GP between the anterior antrum of the right superior pulmonary vein and the superior vena cava (RAGP); and the GP in the superolateral area around the root of the left superior pulmonary vein (LSGP). Published studies showed that the vagal control of SAN was mainly mediated by Ao-SVC GP and RAGP, while the vagal control of AVN contributed to PMLGP and LSGP [ 16 , 19 , 21 , 27 ]. Thus, at our center, we performed the CNA technique by sequentially targeting the Ao-SVC GP, PMLGP, RAGP, and LSGP.…”

“…In 2016, Dr. Aksu et al performed a simplified local fractionated intracardiac electrogram-guided CNA method without the assistance of specific spectral analysis software [ 13 ]. A number of small sample studies have also indicated the feasibility and efficacy of the local fractionated electrogram-guided CNA technique [ 14 , 15 , 16 , 17 ]. However, the research schemes of the CNA technique among published studies are varied.…”

“…However, the research schemes of the CNA technique among published studies are varied. Regarding the target chamber for the CNA technique, the research groups of Dr. Pachon et al [ 9 , 18 ] and Dr. Aksu et al [ 16 , 17 ] ablated all of the atrial GP groups in both atria, while Dr. Yao et al [ 12 , 19 , 20 ] mainly focused on the GP groups in the left atrium and Dr. Debruyne et al [ 21 , 22 ] only ablated the GP groups in the right atrium. Additionally, the endpoint of the CNA procedure is also quite varied among published studies, including the disappearance of vagal responses that are evoked by extracardiac vagal stimulation (ECVS) [ 23 ]; the disappearance of vagal responses evoked by intracardiac HFS or radiofrequency (RF) application [ 12 , 24 ]; the elimination of intracardiac electrograms in targeted GP regions [ 9 , 13 , 16 , 17 ]; the elimination of atropine responses [ 25 ]; and improvements in the bradyarrhythmia or electrophysiological parameters [ 16 , 17 ].…”

“…Regarding the target chamber for the CNA technique, the research groups of Dr. Pachon et al [ 9 , 18 ] and Dr. Aksu et al [ 16 , 17 ] ablated all of the atrial GP groups in both atria, while Dr. Yao et al [ 12 , 19 , 20 ] mainly focused on the GP groups in the left atrium and Dr. Debruyne et al [ 21 , 22 ] only ablated the GP groups in the right atrium. Additionally, the endpoint of the CNA procedure is also quite varied among published studies, including the disappearance of vagal responses that are evoked by extracardiac vagal stimulation (ECVS) [ 23 ]; the disappearance of vagal responses evoked by intracardiac HFS or radiofrequency (RF) application [ 12 , 24 ]; the elimination of intracardiac electrograms in targeted GP regions [ 9 , 13 , 16 , 17 ]; the elimination of atropine responses [ 25 ]; and improvements in the bradyarrhythmia or electrophysiological parameters [ 16 , 17 ]. In other words, a series of urgent questions related to the technical details of the CNA procedure have not been clearly illustrated, such as how to identify optimal candidates and GPs locations; what are the different impacts of sequential GP ablation on the vagal control of the sinoatrial node (SAN) and atrioventricular node (AVN); what are the ablation strategies for patients with different indications; what is the optimal endpoint of the CNA procedure; and what are the long-term outcomes of the CNA technique.…”