First Cardioneural Ablation at the Cleveland Clinic: A Transatlantic Collaboration

A 44-year-old male with a medical history of hypertension, diabetes, and obstructive sleep apnea came for consultation due to recurrent lightheadedness and near syncope. Holter monitoring was obtained, demonstrating vagal sinus pauses up to 8 seconds, vagally mediated complete atrioventricular (AV) block, and paroxysmal atrial fibrillation (AF) (Figure 1). Historically, we would have implanted a permanent pacing system and manage his AF with antiarrhythmic drug therapy. Nevertheless, cardioneural ablation was contemplated as this has recently been described as an adjunctive therapy for select vagally mediated AV block.^1,2

In the presence of paroxysmal AF and AV block, we determined ganglionated plexi (GP) ablation in addition to pulmonary vein isolation (PVI) was the best approach. After discussion with the patient, the procedure was performed under general anesthesia, using propofol and midazolam as induction agents and isoflurane as anesthetic agent. Following transseptal access under intracardiac echocardiographic guidance and heparinization with a target ACT of 350-400, a 20-pole mapping catheter (PENTARAY, Biosense Webster, Inc., a Johnson & Johnson company) was advanced to the left atrium (LA) for construction of LA geometry. Anatomical GP sites were identified by evaluating bipolar atrial electrograms (EGM) annotating low (deflections ≥4 and amplitude <0.7 mV) or high amplitude fractionated EGMs (deflections ≥4 and an amplitude ≥0.7mV) in otherwise healthy atrial myocardium along all 4 pulmonary vein (PV) antrum (Figures 2A-C). Left superior GP (LSGP) is known to be located along the LA superior roof between the left superior PV ridge and the atrial appendage. Right superior GP (RSGP) was noted adjacent to the posterior superior vena caval RSPV junction. Left inferior GP (LIGP) was located within the fat pad below the left inferior PV. Endocardial high-frequency stimulation was not performed due to a lower specificity. Once these sites were noted on our left atrial 3-dimensional map, the mapping catheter was exchanged for an open 3.5 mm irrigated ablation catheter (THERMOCOOL SMARTTOUCH SF, Biosense Webster). Pulmonary vein wide antral isolation was performed encircling each GP site. All ablation was performed at 45W anteriorly and along the roof, 40W on the posterior wall near the esophagus, with an ablation index of 550 anteriorly and 350-400 posteriorly depending on esophageal temperature rise. The order of GP ablation during PV antral isolation was left superior GP, left inferior GP, followed by right superior GP and right inferior GP. This was done so as left superior GP is the most common GP site to elicit vagal response (Figure 3). After left superior GP isolation, no further vagal response was noted during ablation of the LIGP. We then proceeded with targeting right superior pulmonary vein GP. Ablation here resulted in a 15% increase of baseline heart rate. Entrance and exit block was confirmed from each PV with IV adenosine testing. His recovery baseline heart rate has remained elevated for 3 months (Figure 4).

The autonomic nervous system plays a crucial role in the pathophysiology of vagally mediated AF.^3-4 In addition, increased parasympathetic tone may cause paroxysmal AV block, necessitating a permanent pacing system. Aksu et al recently described electrogram-based cardioneural ablation, in which specific anatomical GP sites are targeted with pre-specified vagal response endpoints anticipated.⁵ In view of recent cardioneural ablation outcomes for vagally mediated AV block and data from PVI + GP ablation for freedom of AF, we decided to pursue cardioneural ablation and PVI as our primary approach.⁶ Left atrial PVs, where highly fractionated electrograms along the PV antrum were first annotated, were followed by right PV GP sites. We thought it was important to ablate along the LSGP to elicit a vagal response before RSGP, as ablation along the RSGP may attenuate the vagal response from left PV GP ablations. Our endpoint was abolition of all atrial electrograms along GP sites and vagal response along these sites. At 5-month follow-up, the patient has had no further lightheadedness, syncope, AF, sinus arrest, or AV block.

Electroanatomic mapping-guided cardioneural ablation is feasible in functional AV block and sinus arrest. It is important to understand the concept of this ablation strategy, as it may help avoid permanent pacing system implantation and greatly improve outcomes in young patients.

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@RChung_EP, @MDTolgaAksu

Disclosure: The authors have no conflicts of interest to report regarding the content herein.