Cardioneuroablation for the treatment of reflex syncope and functional bradyarrhythmias: A Scientific Statement of the European Heart Rhythm Association (EHRA) of the ESC, the Heart Rhythm Society (HRS), the Asia Pacific Heart Rhythm Society (APHRS) and the Latin American Heart Rhythm Society (LAHRS)

Abstract

Cardioneuroablation has emerged as a potential alternative to cardiac pacing in selected cases with vasovagal reflex syncope, extrinsic vagally induced sinus bradycardia-arrest or atrioventricular block. The technique was first introduced decades ago, and its use has risen over the past decade. However, as with any intervention, proper patient selection and technique are a prerequisite for a safe and effective use of cardioneuroablation therapy. This document aims to review and interpret available scientific evidence and provide a summary position on the topic.

Keywords: Atrioventricular block; Autonomic nervous system; Reflex syncope; Sinus bradycardia; Vasovagal syncope.

Figure 1

Schematization of cardiovascular regulation by the autonomic nervous system. Sensory nerves transfer signals from mechanoreceptors to cardiovascular (CV) centres in the medulla oblongata. Hypotension evokes a sympathetic response via activation of cardiac sympathetic nerves leading to tachycardia, increased inotropy and vasoconstriction of blood vessels, as well as increased release of catecholamines from the adrenal glands, and vasopressin from the hypophysis. In parallel, parasympathetic inhibition (via a reduction in the central vagal drive) contributes to tachycardia (vagal withdrawal). Conversely, reflex syncope starts with sympathetic withdrawal, vasodilation, and finally vagally mediated cardioinhibition.

Figure 2

Anatomical distribution of ganglionated plexi according to the nomenclature by Armour et al. (Ref.). (A) The left atrium (LA) is seen in the right anterior oblique projection. (B) The LA is seen in the modified posteroanterior view. (C) The right atrium (RA) is seen in the posteroanterior view. (D) Both atria are seen in the posteroanterior view. Red and pink spheres show ablation points in the relevant ganglionated plexus areas. In the LA, RSGP-RIGP can be exposed from the right anterior oblique projection, LSGP can be exposed from the anteroposterior view with cranial tilt, and LIGP-PMLGP can be exposed from the posteroanterior projection, respectively. In the RA, RSGP, RIGP, and PMLGP can be exposed from the posteroanterior projection. Please see the text for other details. CS, coronary sinus; IVC, inferior vena cava; LAA, left atrial appendage; LIGP, inferior (posterolateral) left atrial GP LIPV, left inferior pulmonary vein; LSGP, superior left atrial GP; LSPV, left superior pulmonary vein; MTGP, the Marshall tract GP; PMLGP, posteromedial left atrial GP; RIGP, the inferior (posterior) right atrial GP; RIPV, right inferior pulmonary vein; RSGP, superior (anterior) right atrial GP; RSPV, right superior pulmonary vein; SVC, superior vena cava.

Figure 3

A proposed algorithm for the selection of reflex syncope patients for cardioneuroablation based on available literature. Prolonged ECG monitoring and exercise stress testing might be used to rule out intrinsic sinus or atrioventricular node disease, especially in older patients. AVN, atrioventricular node; CNA, cardioneuroablation; SAN, sinoatrial node.

Figure 4

Electrogram analysis used for the identification of ganglionated plexi. Posteroanterior view of bi-atrial electroanatomical map with ablation clusters at major ganglionated plexi (GPs). (A) Normal bipolar atrial electrogram demonstrating two deflections. (B) Fractionated bipolar atrial electrogram demonstrating more than four deflections. (C) Frequency spectrum of compact myocardium. (D) Frequency spectrum of AF-nest. CS, coronary sinus; IVC, inferior vena cava; LIPV, left inferior pulmonary vein; LSGP, superior left atrial GP; LSPV, left superior pulmonary vein; MTGP, Marshall tract GP; PMLGP, posteromedial left atrial GP; RIPV, right inferior pulmonary vein; RSGP, superior (anterior) right atrial GP; RSPV, right superior pulmonary vein; SVC, superior vena cava.

Figure 5

X-ray-guided extracardiac vagal stimulation. Proper position of the steerable multielectrode catheters inside the left and right internal jugular veins at the base of the skull (close to the jugular foramen) with posteromedial deflection.

Figure 6

Ultrasonography-guided extracardiac vagal stimulation. The location of the pacing electrode in the vicinity of the vagus nerve is seen during ultrasonography-guided extracardiac vagal stimulation.