Cardioneuroablation changes the type of vasovagal response in patients with asystolic reflex syncope

Cardioneuroablation as a strategy to prevent pacemaker implantation in young patients with vasovagal syncope

Background

Cardioneuroablation (CNA) is an ablation technique that targets epicardial ganglionic plexi to reduce syncope burden and avoid pacemaker implantation in patients with cardioinhibitory vasovagal syncope (VVS). This study aims to demonstrate feasibility and safety of CNA in high-risk refractory VVS patients using continuous monitoring with an implantable loop recorder (ILR).

Methods

Data was collected prospectively for patients undergoing CNA. Patients were required to have recurrent syncope with documented asystole, refractory to conservative measures. Ganglionic plexi (GPs) were identified by fragmented signals and high frequency stimulation (HFS). Ablation was performed until loss of positive response to HFS, Wenckebach cycle shortening was achieved, or an increase in sinus rate of > 20 bpm. Follow-up was performed through remote and clinic follow-up of their ILRs.

Results

Between December 2020 and July 2023 six patients (mean age 29 ± 3, 67 % female)underwent CNA. The baseline heart rate and Wenckebach cycle length was 63.2 ± 15 bpm and 582 ms before and 91 ± 5 bpm and 358 ms after ablation respectively. During a median follow-up of 13.4 months, 3/5 patients had no further syncopal episodes, 1 had a recurrence, underwent repeat CNA with no further episodes at 1 year, and 1 had 5 syncopal events, which was a dramatic reduction from nearly daily episodes pre-CNA. There were no procedure related complications.

Conclusions

A dramatic reduction in documented pauses and syncope burden was noted post CNA. Appropriate patient selection with rigorous objective follow-up in an experienced center is necessary. Larger studies are required to confirm these findings.

Shared Decision Making and Cardioneuroablation Allow Discontinuation of Permanent Pacing in Patients with Vagally Mediated Bradycardia

BACKGROUND

Safe discontinuation of pacemaker therapy for vagally mediated bradycardia is a dilemma. The aim of the study was to present the outcomes of a proposed diagnostic and therapeutic process aimed at discontinuing or not restoring pacemaker therapy (PPM) in patients with vagally mediated bradycardia.

METHODS

The study group consisted of two subgroups of patients with suspected vagally mediated bradycardia who were considered to have PPM discontinued or not to restore their PPM if cardioneuroablation (CNA) would successfully treat their bradycardia. A group of 3 patients had just their pacemaker explanted but reimplantation was suggested, and 17 patients had preexisting pacemakers implanted. An invasive electrophysiology study was performed. If EPS was negative, extracardiac vagal nerve stimulation (ECVS) was performed. Then, patients with positive ECVS received CNA. Patients with an implanted pacemaker had it programmed to pace at the lowest possible rate. After the observational period and control EPS including ECVS, redo-CNA was performed if pauses were induced. The decision to explant the pacemaker was obtained based on shared decision making (SDM).

RESULTS

After initial clinical and electrophysiological evaluation, 17 patients were deemed eligible for CNA (which was then performed). During the observational period after the initial CNA, all 17 patients were clinically asymptomatic. The subsequent invasive evaluation with ECVS resulted in pause induction in seven (41%) patients, and these patients underwent redo-CNA. Then, SDM resulted in the discontinuation of pacemaker therapy or a decision to not perform pacemaker reimplantation in all the patients after CAN. The pacemaker was explanted in 12 patients post-CNA, while in 2 patients explantation was postponed. During a median follow-up of 18 (IQR: 8-22) months, recurrent syncope did not occur in the CNA recipients.

CONCLUSIONS

Pacemaker therapy in patients with vagally mediated bradycardia could be discontinued safely after CNA.

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).

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.

Neurally Mediated Syncope in Children and Adolescents: An Updated Narrative Review

Syncope presents a proportion of up to 25% among children and adolescents and accounts for 0.9% of emergency room visits. Its most frequent aetiology is neurally mediated syncope, which includes vasovagal syncope and orthostatic hypotension. Up to 70% of the paediatric population with reflex syncope is female. There are usually precipitating factors and prodromes. This mini-review will discuss the particularities of the clinical presentation, diagnosis, modified Calgary score, indications and accuracy of the head-up tilt test, classification, and pathophysiology in four sequential phases. Prognostic data and the non-pharmacological and pharmacological approaches will also be reviewed and differences regarding reflex syncope in adults will be discussed.