The benefit of cardioneuroablation to reduce syncope recurrence in vasovagal syncope patients: a case-control study

Neuromodulation for Vasovagal Syncope and Bradyarrhythmias

Catheter-based neuromodulation of intrinsic cardiac autonomic nervous system is increasingly being used to improve outcomes in patients with vasovagal syncope and bradyarrhythmias caused by vagal overactivity. However, there is still no consensus for patient selection, technical steps, and procedural end points. This review takes the reader on a practical exploration of neuromodulation for bradyarrhythmias, concentrating on the critical aspects of proper patient selection, evidence-based insights, and anatomic intricacies within the intrinsic cardiac autonomic nervous system. Also discussed are different mapping techniques and outcome measures. Future directions to optimize the utilization of this technique in clinical practice are highlighted.

Cardioneuroablation for vasovagal syncope: insights on patients' selection, centre settings, procedural workflow and endpoints-results from an European Heart Rhythm Association survey

AIMS

Cardioneuroablation (CNA) is a catheter-based intervention for recurrent vasovagal syncope (VVS) that consists in the modulation of the parasympathetic cardiac autonomic nervous system. This survey aims to provide a comprehensive overview of current CNA utilization in Europe.

METHODS AND RESULTS

A total of 202 participants from 40 different countries replied to the survey. Half of the respondents have performed a CNA during the last 12 months, reflecting that it is considered a treatment option of a subset of patients. Seventy-one per cent of respondents adopt an approach targeting ganglionated plexuses (GPs) systematically in both the right atrium (RA) and left atrium (LA). The second most common strategy (16%) involves LA GP ablation only after no response following RA ablation. The procedural endpoint is frequently an increase in heart rate. Ganglionated plexus localization predominantly relies on an anatomical approach (90%) and electrogram analysis (59%). Less utilized methods include pre-procedural imaging (20%), high-frequency stimulation (17%), and spectral analysis (10%). Post-CNA, anticoagulation or antiplatelet therapy is prescribed, with only 11% of the respondents discharging patients without such medication. Cardioneuroablation is perceived as effective (80% of respondents) and safe (71% estimated <1% rate of procedure-related complications). Half view CNA emerging as a first-line therapy in the near future.

CONCLUSION

This survey offers a snapshot of the current implementation of CNA in Europe. The results show high expectations for the future of CNA, but important heterogeneity exists regarding indications, procedural workflow, and endpoints of CNA. Ongoing efforts are essential to standardize procedural protocols and peri-procedural patient management.

Cardioneuroablation for Cardioinhibitory Vasovagal Syncope: Rationale, Approaches, and Its Role in Long-Term Management

Purpose of Review

Cardioneuroablation (CNA) has emerged as a potential alternative to pacemaker therapy in well-selected cases with vasovagal syncope (VVS). In recent years, the number of CNA procedures performed by electrophysiologists has considerably risen. However, some important questions, including proper patient selection and long-term results, remain unanswered. The present article aims to critically review and interpret latest scientific evidence for clinical indications and how to approach long-term management.

Recent Findings

CNA is a new approach that has been supported mainly by retrospective or observational data for its use in syncope. Overall, in mixed population studies treated with CNA, 83.3 to 100% have been reported to be free of syncope over follow-up periods of 6 to 52.1 months. For studies including patients who underwent CNA with pure VVS, 73.2 to 100% have been reported to be syncope-free over follow-up periods of 4 to 45.1 months. One large meta-analysis showed 91.9% freedom from syncope after CAN. To date, only one randomized controlled trial with small case number has been performed of CNA compared to non-pharmacological treatment in VVS. In this study of 48 patients with an average of 10 ± 9 spontaneous syncopal episodes prior to study enrollment and 3 ± 2 episodes in the year prior to CNA. After CNA, 92% were free of syncope compared with 46% treated with optimal non-pharmacological treatment to prevent new syncope episodes (P = 0.0004). To date, most studies have included younger patients (< 60 years of age). There are only limited data in patients older than 60, and some studies suggest less of an effect in relatively older patients.

Summary

Cardioneuroablation can be performed to decrease syncope recurrence in adult patients aged < 60 years, with severe or recurrent cardioinhibitory syncope without prodromal symptoms, after proven failure of conventional therapies. Due to a paucity of data supporting efficacy in older individuals or for vasodepressor components, CNA in adult patients aged > 60 years or in the presence of a dominant vasodepressor should be considered investigational in severely symptomatic patients after proven failure of pharmacological and non-pharmacological therapies.

Potential consequences of cardioneuroablation for vasovagal syncope: A call for appropriately designed, sham-controlled clinical trials

Cardioneuroablation (CNA) is being increasingly used to treat patients with vasovagal syncope (VVS). Bradycardia, in the cardioinhibitory subtype of VVS, results from transient parasympathetic overactivity leading to sinus bradycardia and/or atrioventricular block. By mitigating parasympathetic overactivity, CNA has been shown to improve VVS symptoms in clinical studies with relatively small sample sizes and short follow-up periods (<5 years) at selected centers. However, CNA may potentially tip the autonomic balance to a state of sympathovagal imbalance with attenuation of cardiac parasympathetic activity. A higher heart rate is associated with adverse cardiovascular events and increased mortality in healthy populations without cardiovascular diseases. Chronic sympathovagal imbalance may also affect the pathophysiology of spectra of cardiovascular disorders including atrial and ventricular arrhythmias. This review addresses potential long-term pathophysiological consequences of CNA for VVS.

Cardioneuroablation for the management of patients with recurrent vasovagal syncope and symptomatic bradyarrhythmias: the CNA-FWRD Registry

BACKGROUND

Cardioneuroablation has been emerging as a potential treatment alternative in appropriately selected patients with cardioinhibitory vasovagal syncope (VVS) and functional AV block (AVB). However the majority of available evidence has been derived from retrospective cohort studies performed by experienced operators.

METHODS

The Cardioneuroablation for the Management of Patients with Recurrent Vasovagal Syncope and Symptomatic Bradyarrhythmias (CNA-FWRD) Registry is a multicenter prospective registry with cross-over design evaluating acute and long-term outcomes of VVS and AVB patients treated by conservative therapy and CNA.

RESULTS

The study is a prospective observational registry with cross-over design for analysis of outcomes between a control group (i.e., behavioral and medical therapy only) and intervention group (Cardioneuroablation). Primary and secondary outcomes will only be assessed after enrollment in the registry. The follow-up period will be 3 years after enrollment.

CONCLUSIONS

There remains a lack of prospective multicentered data for long-term outcomes comparing conservative therapy to radiofrequency CNA procedures particularly for key outcomes including recurrence of syncope, AV block, durable impact of disruption of the autonomic nervous system, and long-term complications after CNA. The CNA-FWRD registry has the potential to help fill this information gap.

Cardioneuroablation for the Treatment of Vasovagal Syncope: Current Status and Impact on Quality of Life

PURPOSE OF REVIEW

Vasovagal syncope (VVS) is a common entity causing transient loss of consciousness and affecting quality of life. Guideline-recommended therapy involves conservative measures and pacing in selected patients. Cardioneuroablation (CNA) targeting the ganglionated plexi in the heart has been shown to reduce excessive vagal excitation, which plays a major role in the pathophysiology of VVS and functional bradycardia.

RECENT FINDINGS

The introduction of CNA has fueled research into its value for the treatment of VVS. Multiple observational studies and one randomized trial have demonstrated the safety and efficacy of CNA and the positive impact on quality of life. This review describes the rationale and CNA procedural techniques and outcomes. Patient selection and future directions have also been described. Cardioneuroablation is a promising treatment for patients with recurrent VVS and functional bradycardia. Further large-scale randomized studies are needed to further verify the safety and efficacy of this approach.

Cardioneuroablation for successful treatment of symptomatic bradycardia in a 12-year-old child after a 6-month follow-up

Background

Cardioneuroablation (CNA) is recognized as a promising therapeutic option for adults with severe symptomatic bradycardia caused by excessive vagal tone. However, no pediatric cases have been reported to date. Therefore, the aim of this study is to evaluate the feasibility and efficacy of CNA in children.

Methods

A 12-year-old male patient was hospitalized with symptoms of fatigue, palpitations, and syncope for more than 2 months, and was definitively diagnosed with functional sinoatrial node dysfunction by using a 12-lead electrocardiogram, 24-h Holter monitoring, loading dose of atropine test (0.04 mg/kg), and treadmill exercise test. Simultaneously, whole-exome sequencing was performed on the child and his core family members. After completing the preoperative examination and signing the informed consent form, the child underwent CNA therapy.

Results

First, the electroanatomic structures of both atria were mapped out by using the Carto 3 system, according to the protocol of purely anatomy-guided and local fractionated intracardiac electrogram-guided CNA methods. Then, the local fractionated intracardiac electrograms of each cardiac ganglionated plexus (GP), including the GP between the aortic root and the medial wall of the superior vena cava, the GP between the posterior wall of the coronary sinus ostium and the left atrium, the GP between the anterior antrum of the right superior pulmonary vein and the superior vena cava, the GP in the superolateral area around the root of the left superior pulmonary vein, the GP around the root of the right inferior pulmonary vein, and the GP around the root of the left inferior pulmonary vein, were used as targets for ablation at a power of 30 W with an ablation index of 350-400. At a 6-month follow-up, the child's heart rhythm saw a complete restoration to sinus rhythm and clinical symptoms disappeared.

Conclusion

The first application of CNA in a child with symptomatic sinus bradycardia was achieved with better clinical outcomes. CNA can be carried out cautiously in children under suitable indications.

Cardioneuroablation for neurally-mediated syncope: Initial experience

Cardioneuroablation is an emerging alternative therapeutic modality for young patients with severe neurally-mediated syncope. We present two images of cardioneuroablation performed in young patients who suffered from recurrent neurally-mediated syncope with asystole and functional atrioventricular block. The patients remain syncope-free during follow-ups.

Importance of resting heart rate

Resting heart rate is a determinant of cardiac output and physiological homeostasis. Although a simple, but critical, parameter, this vital sign predicts adverse outcomes, including mortality, and development of diseases in otherwise normal and healthy individuals. Temporal changes in heart rate can have valuable predictive capabilities. Heart rate can reflect disease severity in patients with various medical conditions. While heart rate represents a compilation of physiological inputs, including sympathetic and parasympathetic tone, aside from the underlying intrinsic sinus rate, how resting heart rate affects outcomes is uncertain. Mechanisms relating resting heart rate to outcomes may be disease-dependent but why resting heart rate in otherwise healthy, normal individuals affects outcomes remains obscure. For specific conditions, physiologically appropriate heart rate reductions may improve outcomes. However, to date, in the normal population, evidence that interventions aimed at reducing heart rate improves outcomes remains undefined. Emerging data suggest that reduction in heart rate via vagal activation and/or sympathetic inhibition is propitious.

Ganglionated Plexus Ablation Procedures to Treat Vasovagal Syncope

Vasovagal syncope (VVS) refers to a heterogeneous group of conditions whereby the cardiovascular reflexes normally controlling the circulation are interrupted irregularly in response to a trigger, resulting in vasodilation, bradycardia, or both. VVS affects one-third of the population at least once in their lifetime or by the age of 60, reduces the quality of life, and may cause disability affecting certain routines. It poses a considerable economic burden on society, and, despite its prevalence, there is currently no proven pharmacological treatment for preventing VVS. The novel procedure of ganglionated plexus (GP) ablation has emerged rapidly in the past two decades, and has been proven successful in treating syncope. Several parameters influence the success rate of GP ablation, including specific ablation sites, localization and surgical techniques, method of access, and the integration of other interventions. This review aims to provide an overview of the existing literature on the physiological aspects and clinical effectiveness of GP ablation in the treatment of VVS. Specifically, we explore the association between GPs and VVS and examine the impact of GP ablation procedures as reported in human clinical trials. Our objective is to shed light on the therapeutic significance of GP ablation in eliminating VVS and restoring normal sinus rhythm, particularly among young adults affected by this condition.

Cardioneuroablation for Treating Vasovagal Syncope: Current Status and Future Directions

Syncope is defined by transient and spontaneous loss of consciousness with rapid recovery. Vasovagal syncope (VVS) is the most common form of syncope and is strongly associated with hypervagotonia. There is, however, a lack of effective therapies for VVS. Cardioneuroablation (CNA) is an emerging and promising intervention for VVS with favourable outcomes. CNA has been shown to suppress excessive excitation of vagal activity through ablating the cardiac ganglionated plexi. CNA in the management of VVS requires more structured and comprehensive studies and several issues concerning patient selection, selection of ablation targets, ablation endpoints and the long-term effect of CNA are yet to be determined. This review describes its clinical applications and future directions based on current research data and the authors' own experiences.

Cardioneuroablation for Reflex Syncope: Efficacy and Effects on Autonomic Cardiac Regulation-A Prospective Randomized Trial

BACKGROUND

Treatment of cardioinhibitory vasovagal syncope (VVS) is difficult. Recently, cardioneuroablation (CNA) has emerged as a new therapeutic option.

OBJECTIVES

This study sought to assess the effects of CNA on syncope recurrences in patients with VVS.

METHODS

This study was a prospective, open, randomized, controlled, investigator-initiated trial comparing CNA versus optimal nonpharmacologic therapy in patients with cardioinhibitory VVS. Patients were included if they had documented symptomatic cardioinhibitory or mixed VVS and positive atropine test. CNA was performed using radiofrequency ablation of the ganglionated plexi from the left and right atria. Follow-up lasted 2 years. Primary endpoint was time to first syncope recurrence. Secondary endpoints included changes in sinus rhythm and heart rate variability measured in Holter electrocardiography at baseline and 3, 12, and 24 months after CNA, as well as changes in quality of life at baseline and after completion of follow-up.

RESULTS

A total of 48 patients (17 male, mean age 38 ± 10 years, 24 in CNA group, 24 in control group) entered the study. The primary endpoint occurred in 2 patients (8%) from the CNA group versus 13 control patients (54%) (P = 0.0004). After CNA the mean sinus rhythm at 24-hour Holter electrocardiography was significantly faster and heart rate variability parameters significantly changed toward parasympathetic withdrawal compared with baseline values. Quality of life significantly improved in the CNA group (30 ± 10 points vs 10 ± 7 points; P = 0.0001), whereas it remained stable in control patients (31 ± 10 points vs 30 ± 10 points; P = 0.5501).

CONCLUSIONS

This is the first randomized study documenting efficacy of CNA in patients with cardioinhibitory VVS. Larger studies are needed to confirm these findings. (Cardioneuroablation for Reflex Syncope [ROMAN]; NCT03903744).

Ganglionic Plexus Ablation: A Step-by-step Guide for Electrophysiologists and Review of Modalities for Neuromodulation for the Management of Atrial Fibrillation

As the most common sustained arrhythmia, AF is a complex clinical entity which remains a difficult condition to durably treat in the majority of patients. Over the past few decades, the management of AF has focused mainly on pulmonary vein triggers for its initiation and perpetuation. It is well known that the autonomic nervous system (ANS) has a significant role in the milieu predisposing to the triggers, perpetuators and substrate for AF. Neuromodulation of ANS - ganglionated plexus ablation, vein of Marshall ethanol infusion, transcutaneous tragal stimulation, renal nerve denervation, stellate ganglion block and baroreceptor stimulation - constitute an emerging therapeutic approach for AF. The purpose of this review is to summarise and critically appraise the currently available evidence for neuromodulation modalities in AF.

Permanent pacing versus cardioneuroablation for cardioinhibitory vasovagal syncope

BACKGROUND

We compared the efficacy and safety of cardioneuroablation (CNA) vs. permanent pacing (PM) for recurrent cardioinhibitory vasovagal syncope (CI-VVS).

METHODS

One hundred sixty-two patients (CNA = 61, PM = 101), age 36 + 11 years) with syncope frequency of 6.7 ± 3.9/year were included in this multicenter study. All patients with CNA were provided by a single center, while patients with PM were provided by 4 other centers. In the CNA arm, an electroanatomic mapping guided approach was used to detect and ablate ganglionated plexus sites. Dual chamber rate drop response (RDR) or close loop stimulation (CLS) transvenous and leadless pacemakers were implanted using standard technique. The primary endpoint was freedom from syncope.

RESULTS

Of 101 patients in the PM group, 39 received dual-chamber pacemaker implants with the CLS algorithm, 38 received dual-chamber pacemakers with the RDR algorithm, and 24 received a leadless pacemaker. At 1-year follow-up, 97% and 89% in the CNA and PM group met the primary endpoint (adjusted HR = 0.27, 95% CI 0.06-1.24, p = 0.09). No significant differences in adverse events were noted between groups. There was no significant association between age (HR:1.01, 95% CI 0.96-1.06, p = 0.655), sex (HR:1.15, 95% CI 0.38-3.51, p = 0.809), and syncope frequency in the past year (HR:1.10, 95% CI 0.97-1.25, p = 0.122) and the primary outcome in univariable analyses.

CONCLUSIONS

After adjustment for patient characteristics, the medium-term syncope recurrence risk of CI-VVS patients who underwent CNA was similar to that of a population of patients undergoing pacemaker implantation with a similar safety profile.

Cardioneuroablation for vasovagal syncope: A systematic review and meta-analysis

BACKGROUND

Cardioneuroablation (CNA) has emerged as promising therapy for patients with refractory vasovagal syncope (VVS).

OBJECTIVE

The purpose of this study was to provide a freedom from syncope estimate for CNA, including subgroup analysis by method and target of ablation.

METHODS

A systematic search was performed in MEDLINE and EMBASE according to the PRISMA guidelines until February 14, 2022. Observational studies and clinical trials reporting freedom from syncope were included. Meta-analysis was performed with a random-effects model.

RESULTS

A total of 465 patients were included across 14 studies (mean age 39.8 ± 4.0 year; 53.5% female). Different techniques were used to guide CNA: 50 patients (10.8%) by mapping fractionated electrograms, 73 (15.7%) with the spectral method, 210 (45.2%) with high-frequency stimulation, 73 (15.7%) with a purely anatomically guided method, and 59 (12.6%) with a combination. The target was biatrial in 168 patients (36.1%), left atrium only in 259 (55.7%), and right atrium only in 38 (8.2%). The freedom from syncope was 91.9% (95% confidence interval [CI] 88.1%-94.6%; I2 = 6.9%; P = .376). CNA limited to right atrial ablation was associated with a significant lower freedom from syncope (81.5%; 95% CI 51.9%-94.7%; P <.0001) vs left atrial ablation only (94.0%; 95% CI 88.6%--6.9%) and biatrial ablation (92.7%; 95% CI 86.8%-96.1%). Subgroup analysis according to the technique used to identify ganglionated plexi did not show any significant difference in freedom from syncope (P = .206).

CONCLUSION

This meta-analysis suggests a high freedom from syncope after CNA in VVS. Well-designed, double-blind, multicenter, sham-controlled randomized clinical trials are needed to provide evidence for future guidelines.

The future of cardioneuroablation in cardiovascular medicine

INTRODUCTION

Cardioneuroablation is increasingly being utilized to improve outcomes in patients with vagally mediated bradyarrhythmias. However, there are still controversial issues in the field including patient selection, safety and efficacy, and procedural end-points.

AREAS COVERED

In this review, the current role of cardioneuroablation is summarized, and controversial issues related to the modality are discussed.

EXPERT OPINION

According to small open-label cohort studies, overall freedom from syncope recurrence was higher than 90% after cardioneuroablation in patients with vasovagal syncope (VVS). Use of the electrogram-based strategy or high-frequency stimulation demonstrate similar success rate except in procedures limited to the right atrium. Based on a recently published randomized controlled trial and metanalysis, it may be possible now to make a strong recommendation for cardioneuroablation in patients <40 years of age, and those with the cardioinhibitory or mixed type of VVS who continue to experience frequent and/or burdensome syncope recurrences. Considering patients with VVS are prone to significant placebo/expectation effect, sham-controlled trials may help to quantify the placebo effect. In well-selected patients with functional atrioventricular block and sinus bradycardia, may result in encouraging medium-term outcomes. However, functional bradycardia is identified in a minority of patients presenting with high-grade atrioventricular block or sinus node dysfunction.

Pericarditis following left atrial ablation

We aimed to evaluate the incidence of acute pericarditis following cardioneuroablation (CNA) and to compare this with patients undergoing left atrial (LA) radiofrequency ablation for atrial fibrillation (AF). This is a single-center prospective study. During the study period, CNA for vasovagal syncope was performed in 42 patients, pulmonary vein isolation (PVI) for paroxysmal AF in 46 patients, and posterior wall isolation (PWI) in addition to PVI for persistent AF in 22 patients. Pericarditis was reported by 18 (16.4%) patients overall: 1 (2.4%) patient in CNA group, 8 (17.4%) patients in PVI group, and 9 (40.9%) patients in PWI (p<0.001). On univariable logistic regression analysis, CNA was associated with a lower risk of pericarditis (odds ratio 0.11, 95% CI 0.01-0.97), while ablation of PWI plus PVI was associated with a higher risk of pericarditis compared with PVI (odds ratio 3.29, 95% CI 1.05-10.3). This study shows that pericarditis is extremely uncommon following CNA and is significantly less frequent than following AF ablation. This difference is likely related to the much lower amount of LA ablation necessary in this group. This article is protected by copyright. All rights reserved.

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

Cardioneuroablation (CNA) is proposed as a promising therapy for patients with sinoatrial node dysfunction (SND) that is mediated by excessive vagal tone. However, a series of urgent questions about CNA remain unanswered. From December 2020 to March 2022, six patients with symptomatic SND who underwent CNA were summarized in this report. Sequential CNA targeting Ao-SVC GP, PMLGP, RAGP, and LSGP was performed in patients, guided by fractionated intracardiac electrograms and dynamically evaluated by extracardiac vagal stimulation (ECVS). The results showed that Ao-SVC GP ablation led to a significant increase in heart rate (HR) and the elimination of sinus arrest evoked by ECVS, while the vagal responses of atrial ventricular block were eliminated by the ablation of PMLGP and LSGP. Post-procedure HR increased up to 64-86% of the maximum HR of an atropine test at baseline. The median HR from Holter monitoring increased from 52.8 ± 2.1 bpm at baseline to 73.0 ± 10.4 bpm after the procedure (p = 0.012) and to 71.3 ± 10.1 bpm at the six-month follow-up (p = 0.011). Bradycardia-related symptoms disappeared in all patients at the six-month follow-up. This case series reveals the feasibility of using the ECVS-assisted sequential CNA technique and indicates the critical role of ECVS in dynamically evaluating the impact of sequential CNA on the vagal control of SAN and AVN.