Jose Carlos Pachon-M

Aims: Cardioneuroablation (CNA) attenuates excessive parasympathetic input to the sinus and atrioventricular (AV) nodes by ablating atrial ganglionated plexi (GP), while preserving sympathetic innervation and intrinsic nodal function. It offers a mechanism-directed alternative to permanent pacing in selected patients with reflex syncope, functional AV block, or symptomatic vagally mediated sinus bradycardia. This review translates that physiological rationale into a practical, reproducible procedural framework. Methods and Results: Current evidence is synthesised with the collective procedural experience of the writing group. Successful implementation rests on careful patient selection, accurate identification of the cardioinhibitory phenotype, and a structured, physiology-guided procedure. Implantable loop recorders are central to documenting spontaneous events and distinguishing sinus- from AV-nodal mechanisms, complemented by tilt-table and atropine testing. During ablation, extracardiac vagal stimulation (ECVS) provides the most robust physiological endpoint for confirming vagal attenuation; where ECVS is unavailable, surrogate markers can guide the procedure, albeit with recognised limitations. Practical workflows are set out, including phenotype-driven GP targeting, the ablate–test–ablate sequence, and distinct strategies for sinus-node– and AV-node–predominant phenotypes. Technical considerations, safety, laterality of ablation, and challenging scenarios—recurrence after apparently successful CNA, athletes with functional bradyarrhythmias, and CNA during atrial fibrillation ablation—are also addressed. Conclusion: By emphasising procedural implementation and physiological endpoints, and situating CNA within the broader management of vagally mediated bradyarrhythmias, this review offers a reproducible, phenotype-guided framework to support its safe and effective use. It reflects current evidence and accumulated procedural experience rather than formal recommendation.

Background: Vagally mediated syncope and functional bradyarrhythmias can cause recurrent symptoms, injury and a need for permanent pacing, yet standard therapies do not address the underlying autonomic reflex. Cardioneuroablation (CNA) targets this mechanism, but adoption has been limited by uncertainty about patient selection, procedural endpoints and durable outcomes. Methods: We studied 95 consecutive patients with vagally mediated syncope (n=78) or functional bradyarrhythmia (n=17) who underwent CNA at a single center by a single lead operator under a uniform, prospectively maintained protocol. Extracardiac vagal stimulation (ECVS) was performed before and after ablation to confirm vagally mediated sinus or atrioventricular (AV) nodal responses and to verify their attenuation. Outcomes through 1 year included clinical recurrence, quality of life, pacing burden and pacemaker extraction. Results: Before ablation, ECVS provoked sinus pauses in 95.8% of patients and AV block in 91.6%; after ablation, sinus pauses were abolished in every patient and residual AV block was present in 4.2%. One-year freedom from recurrent syncope and from bradyarrhythmia-related events was 93.8% and 94.1%. Syncope burden fell from a median of 2.7 episodes per year to none, and disease-specific quality of life improved substantially (P<0.001). Among patients with pre-existing devices, atrial pacing burden fell from a median of 22% to 0%. There were no strokes, deaths or myocardial infarctions. Conclusions: In this single-center cohort, physiology-guided CNA was associated with durable symptom control, improved quality of life and reduced pacing across vagally mediated bradyarrhythmia syndromes. Multicenter controlled studies are needed to confirm these findings.

Background Currently, there is no reliable endpoint for the conclusion of atrial fibrillation (AF) ablation. Atrial burst pacing and/or isoproterenol challenge are poor diagnostic tools. A newly proposed Vagal AF Induction Test(VAFIT) uses effective atrial refractory period measurement, simultaneously with extra-cardiac vagal stimulation(ECVS) to study AF inducibility pre and post-ablation. Objective Prospective study in patients submitted to radiofrequency catheter pulmonary vein isolation(PVI) plus cardioneuroablation(CNA) evaluating the VAFIT result before and at the end of the procedure with AF recurrence. Methods Prospective study of 142 patients, 57.5[48.9-70.2] years-old, 71% males, with symptomatic AF (79.6% paroxysmal/20.4% persistent), left atrium diameter of 38.0[35.0-41.2] mm, and left ventricular ejection fraction of 63.0 [62.0-68.2]. VAFIT was considered positive or negative depending on whether AF induction occurred. It was performed at baseline and after PVI+CNA, with a single atrial extra stimulus during ECVS (5s/50Hz/1V/kg up to 70V/Pulse Width=50 µs). Patients were followed for a median of 15.0[7.0-20.0] months. The association of VAFIT-positive status at the end of the procedure with AF recurrence was investigated by univariate and multivariate Cox regression analysis. Results Pre-ablation VAFIT was positive in all cases and became negative in 62.9% of patients. AF recurrence: 18.7% in VAFIT-positive and 5.6% in VAFIT-negative patients(p=0.012). VAFIT-positivity was associated with AF recurrence (HR: 4.56(1.37-15.23,p=0.014). Conclusion A VAFIT-positive status following PVI+CNA was strongly and independently associated with AF recurrence. It remains to be investigated in randomized studies whether achieving VAFIT-negativity at the end of the procedure, as demonstrated in this study, would lead to better clinical outcomes.

Background: The differential diagnosis of supraventricular tachycardias (SVTs) is essential during radiofrequency‐(RF) ablation. The extracardiac vagal stimulation (ECVS), introduced in 2015, offers new insights for electrophysiological studies and ablation, allowing controlled cardiac vagal effect. Methods: Prospective study of 625 SVT ablation patients. ECVS was performed using a regular electrophysiology catheter to study atrioventricular (AV) and ventriculo‐atrial (VA) conduction and their effects on tachycardia. Baseline ECVS was performed to determine the optimal position for right or left ECVS, near the jugular foramen. ECVS was repeated during atrial and ventricular pacing (VP) to monitor the procedure's progression and ensure successful endpoints. Results: ECVS was successful in 611/625 patients (98%), 381 (62.3%) had AV node reentry tachycardia‐(AVNRT), and 230 (37.6%) accessory pathway (AP), including 135‐(58.7%) anterograde AP (WPW) and 95 (41.3%) concealed AP. ECVS + VP in 33 patients with atypical AVNRT yielded VA block in 32‐(97%), suggesting VA conduction solely via the AV node. In contrast, 57 patients with concealed para‐septal AP maintained VA conduction during ECVS, confirming AP. ECVS proved to be a fast, reliable, and practical additional EP tool: VA block indicated AVNRT, while persistent VA conduction suggested AP. Additionally, ECVS was highly effective in revealing and confirming successful AP ablation by demonstrating the absence of AV and VA anomalous conduction. Conclusion: ECVS was a valuable tool in the diagnosis and ablation of SVTs. It allowed reproducible AV and VA block through normal pathways, easily identifying AVNRT and concealed, intermittent, or subtle AP. It was particularly useful in complex cases involving concealed AP and atypical AVNRT tachycardia.

Neurocardiogenic syncope (NCS) is traditionally considered a benign yet perplexing condition, characterized by transient loss of consciousness due to reflex bradycardia and hypotension. Why would Nature create a reflex that stops the heartbeat, risking collapse, injury, or even death? Our observations, based on Cardioneuroablation and high number of NCS patients, suggest that this reflex may have evolved as a primitive survival mechanism probably to mitigate blood loss during hemorrhage improving the survival likelihood in primitive cold-blooded aquatic animals. Over millions of years, this reflex has persisted as a vestigial trait, despite significant physiological changes in modern homeothermic organisms. 2 This review examines how this condition evolved from an aneural heart to the modern autonomic nervous system, with particular emphasis on the vagus nerve's development and its role from early vertebrates. It discusses the transition from cold-blooded to warm-blooded life forms, highlighting how changes in metabolic demands and circulatory regulation have rendered the once-beneficial cardioinhibitory reflex into a maladaptive in present-day humans.

Currently, there is no reliable endpoint for the conclusion of atrial fibrillation (AF) ablation. Atrial burst pacing and/or isoproterenol challenge are poor diagnostic tools. A newly proposed vagal AF induction test (VAFIT) uses effective atrial refractory period measurement, simultaneously with extra-cardiac vagal stimulation (ECVS) to study AF inducibility pre- and post-ablation. This is a prospective study in patients submitted to radiofrequency catheter pulmonary vein isolation (PVI) plus cardioneuroablation (CNA) evaluating the VAFIT result before and at the end of the procedure with AF recurrence. Prospective study of 142 patients, 57.5 (48.9-70.2) years old, 71% males, with symptomatic AF (79.6% paroxysmal/20.4% persistent), left atrium diameter of 38.0 (35.0-41.2) mm, and left ventricular ejection fraction of 63.0 (62.0-68.2). VAFIT was considered positive or negative depending on whether AF induction occurred. It was performed at baseline and after PVI + CNA, with a single atrial extra stimulus during ECVS (5 s/50 Hz/1 V/kg up to 70 V/pulse width = 50 µs). Patients were followed for a median of 15.0 (7.0-20.0) months. The association of VAFIT-positive status at the end of the procedure with AF recurrence was investigated by univariate and multivariate Cox regression analysis. Pre-ablation VAFIT was positive in all cases and became negative in 62.9% of patients. AF recurrence: 18.7% in VAFIT-positive and 5.6% in VAFIT-negative patients (p = 0.012). VAFIT-positivity was associated with AF recurrence (HR 4.56 (1.37-15.23, p = 0.014). A VAFIT-positive status following PVI + CNA was strongly and independently associated with AF recurrence. VAFIT negative status reduced 4.5 times the post-ablation AF recurrence. It remains to be investigated in randomized studies whether achieving VAFIT-negativity at the end of the procedure, as demonstrated in this study, would lead to better clinical outcomes.