Vagal AF Induction Test (VAFIT): A New Endpoint for Optimizing Atrial Fibrillation Ablation through Cardioneuroablation

Vagal AF Induction Test (VAFIT): A New Endpoint for Optimizing Atrial Fibrillation Ablation through Cardioneuroablation | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Vagal AF Induction Test (VAFIT): A New Endpoint for Optimizing Atrial Fibrillation Ablation through Cardioneuroablation JC Pachon-M, Enrique I Pachon-M, Tomas G santillana-P, Tasso J Lobo, and 4 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-5643881/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Introduction 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. 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. Cardiac & Cardiovascular Systems Atrial Fibrillation ablation cardioneuroablation pulmonary vein isolation denervation autonomic nervous system syncope refractory dispersion Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Introduction Despite significant advancements, a functional endpoint for AF ablation has yet to be established 1 . Inducing AF with a single extra stimulus in the EP lab is very rare. Furthermore, it would be remarkable if a single extra stimulus during the EARP could trigger any atrial activity, let alone induce atrial fibrillation. However, we found that a single extra stimulus, applied under vagal action by ECVS during the basal value of EARP, can elicit atrial responses and induces AF in virtually all patients – Vagal AF Induction Test: VAFIT positive. This response is suppressed by CNA, which can successfully convert a positive VAFIT to negative. In this article, we will investigate whether achieving a negative VAFIT at the conclusion of AF ablation via CNA impacts long-term recurrence rates. The aim of this article is to study the long-term recurrence following AF ablation through PVI combined with CNA, comparing groups that concluded the procedure with a VAFIT-positive versus VAFIT-negative status. Methods A prospective cohort study involving 142 patients, including 101(71.1%) males with a mean age of 57.5 [48.9-70.2]years, with symptomatic AF, either paroxysmal (79.6%) or persistent (20.4%), refractory to medication, and without significant heart disease. The mean LA size was 38.0[35.0-41.2]mm, and the EF was 0.63[0.62-0.68]. Patients underwent PVI and CNA by RF catheter ablation, with denervation success confirmed by ECVS. The cohort was followed for up to 40 months (5 to 40 with median of 15 months) to monitor AF recurrence, comparing those with negative versus positive VAFIT. Ethics Declaration This study was conducted as part of our regular clinical application of ablation treatments approved for patients treated at our hospital. Each patient provided written informed consent before treatment following a detailed in-person interview that thoroughly explained the procedure’s objectives, potential risks, and benefits. The study fully adhered to the ethical principles outlined in the Declaration of Helsinki, ensuring the protection of the rights, safety, and well-being of the patients. Robust measures were implemented to safeguard the patients’ safety and data collected during the study in compliance with local regulatory requirements and international ethical standards. Inclusion criteria Included patients met the following criteria: 1. Paroxysmal or persistent AF with episodes lasting < 1 year in accordance with the 2014 AHA/ACC/HRS guidelines 7 . 2. Age: 20 to 80 years. 3. Refractoriness or impossibility of pharmacological treatment. 4. Absence of, or mild, cardiomyopathy and no significant systemic pathology. 5. Ability to comply with the written informed consent, with the study, and with the follow-up. Exclusion Criteria Those who met any of the following criteria: 1. Previous cardiac surgery or AF ablation. 2. AF lasting over 1 year (long-standing AF). 3. Valvar disease or cardiomyopathy (EF15 mm) or coronary artery disease. 5. Contraindication to anticoagulants (heparin, warfarin, NOAC). 6. LA diameter >55 mm. 7. NYHA Heart Failure Class > I, cerebrovascular or important organic or metabolic disease. 8. Anatomical impossibility to perform ECVS. 9. Current or planned pregnancy. Extracardiac Vagal Stimulation (ECVS) ECVS was performed without dissection or direct contact with the vagus nerve, Figure 1, following the original technique 2 . An EP lead was advanced through the superior vena cava and internal jugular vein up to the right jugular foramen, Figure 1-A), usually the closest location to the vagus nerve. ECVS was achieved by using a neurostimulator, Figure 1-A1, delivering a pulsed electric field (Amplitude of 1V/kg body weight up to 70V, pulse width of 50 microseconds, at a frequency of 50Hz for 5 seconds) within the jugular vein. The typical response includes transient asystole and/or AV block, Figure 1-A2. Additionally, the VAFIT protocol was implemented, as detailed below. ECVS was performed prior to ablation to assess the basal response, during the procedure to guide denervation progress, and at the end of the procedure to confirm the endpoint. Methodology for VAFIT: Vagal Atrial Fibrillation Induction Test (see video) The EARP was determined at baseline on the antero-lateral right atrium and in the posterior left atrium by coronary sinus, Figure 2-A. It was then reassessed during ECVS, starting at a coupling interval of 80ms and increasing by 20ms at each step until capture occurred. Induction of AF was classified as VAFIT-positive, Figure 2-B, and its absence as VAFIT-negative, Figure 2-C. Following CNA, EARP assessment and VAFIT were repeated. Any changes in EARP, VAFIT results, and the presence or absence of arrhythmias were systematically documented. Radiofrequency Ablation All procedures involved orotracheal intubation, general intravenous anesthesia monitored by BIS Spectral Monitoring System, Medtronic, Minneapolis, MN, USA, and transesophageal echocardiography. Parasympatholytic drugs were withheld for the last two days prior to the procedure. A conventional recorder and the NAVX-Ensite® Velocity/Precision Cardiac Mapping System, Abbott, IL, USA were employed. RF Catheter was guided by 3D electroanatomic mapping supplemented with fluoroscopy through the femoral vein using the Seldinger technique. A duodecapolar catheter was positioned in the coronary sinus, and the LA was accessed via transseptal puncture. HD-Grid or a decapolar circular catheter Abbott, IL, USA was used to create 3D anatomical models and a fractionation map simultaneously. Conventional PVI 3,4 proceeded using the Abbott FlexAbility Ablation Catheter with 40W/42 o C/17ml/minute. An activated clotting time of 300 to 400 seconds was maintained with an intravenous heparin infusion. Cardioneuroablation After PVI, stepwise CNA was performed targeting the P-area17 (Figure 1-F), the four main ganglionated plexi (Figure 1-B, E, F, G), and AF-Nests 5 , 6 ,16, 7 including the Marshall’s vein area 8 , (Figure 1-C,D), in both atria aiming to achieve either complete elimination or significant attenuation of the vagal effect 9 . The P area is a region of the left interatrial septum between the insertion of the right PVs, the LA roof, and the fossa ovalis. Typically, ablation of this area causes the greatest denervation of P cells. Interestingly, it corresponds to the area of the ancient Ludwig ganglion described in amphibians in the 19th century17,28. If necessary, additional AF-Nests were identified using filtered recordings (300-500Hz, Figure 1-C) and/or fractionation mapping at the operator’s discretion, Figure 1-E,F,G, until the elimination or significant attenuation of the vagal effect. Endpoint The PVI endpoint was the conventional PV isolation. The CNA endpoint (denervation) was the elimination or 90% attenuation of the vagal response by ECVS, Figure 1-A2 and Figure 3-C. The denervation criteria are shown in Table 1. Given the wide vagal innervation throughout the atrium, the protocol included denervation criteria across three distinct vagal innervation domains: Table 1 – Vagal domains identified by ECVS with respective innervation and denervation criteria. AV: Atrioventricular; VAFIT: Vagal AF Induction Test; EARP: Effective Atrial Refractory Period Domain Protocol Pre-CNA Innervation Criteria Post-CNA Denervation Criteria 1. Sinus Node 1. Basal Sinus Rhythm 1. Sinus Arrest/Pause 1. Sinus rhythm 2. AV Node 2. Atrial Pacing 2. AV Block 2. No AV Block 3. Atrial Wall 3. EARP measurement + VAFIT 3. Significant EARP reduction 3. Abolishment of vagal EARP shortening 4. VAFIT-positive 4. VAFIT-negative Follow-up Patients were followed for up to 40 months (median of 15[IQR:7-20]) with evaluations at 30, 60, 120 days, and subsequently every six months. They were instructed to document any arrhythmias or symptoms using ECG, Holter monitoring, Kardia device, or smartwatches with ECG, and to immediately transmit the recordings or visit the emergency department if they experienced any sustained arrhythmias. Patients were also encouraged to report any symptoms directly, by phone, email, or through social media. Exercise testing and Holter monitoring were conducted after 3 and 6 months, then annually, and as needed if symptoms occurred. Recurrence was defined as any AF/AT episode lasting more than 30 seconds. Statistical analysis The Pearson Chi-Squared test and Fisher’s exact test were chosen to assess the independence of categorical data between groups. The distribution of continuous variables was evaluated using the Shapiro-Wilk test. Results for continuous variables are reported as mean ± standard deviation for normally distributed data, and median with interquartile ranges for data not normally distributed, analyzed with non-parametric tests. For continuous variables that assumed a normal distribution but potentially had unequal variances, robust Welch’s t-test was employed. The Mann-Whitney U test was used to compare medians of variables that were not normally distributed. Event-free survival rates were estimated using the Kaplan-Meier model, with differences between groups assessed using the log-rank test. Cox regression was utilized for both univariate and multivariate analyses to determine hazard ratios, with the proportional hazard assumption tested for validity. Statistical significance was set at a two-sided p-value of less than 0.05. Data analysis was conducted using SPSS (version 28.0.1.1) and the latest version of Jamovi (2023, Version 2.4.14.0). Results Pre-ablation ECVS showed significant vagal responses in every case and VAFIT was also positive in all cases. Post-Ablation VAFIT became negative in 89(62.9%) and persisted positive, with sustained or non-sustained AF reinduction, in 53(37.1%) cases. In the initial phase (142 patients), VAFIT was positive, and AF was sustained in 29 cases (20.4%). In the final phase, VAFIT was positive in 53 patients with sustained AF in 4 cases (7.5%), p=0.003. In the comparison of post-ablation results the VAFIT was negative in 89 and positive in 53 patients. AF recurrence was significantly higher in the VAFIT-positive group (18.7%) compared to the VAFIT-negative group (5.6%, p=0.012). This indicates a statistically significant association between VAFIT-positive status and recurrence of AF post-ablation, HR=4.56(1.37-15.23, p=0.014). Table 2 displays the results and the statistical treatment between the VAFIT-negative and Positive groups. The groups show similar characteristics except for a higher AF recurrence in the VAFIT-positive group, (p=0.012). These results suggest that in this cohort, while persistent VAFIT-positive status is associated with higher AF recurrence, other demographic and clinical parameters do not appear to differ significantly between both groups, Figure 4 on the right. Table 2 - Clinical and Demographic Parameters between VAFIT-negative and Positive Groups. VAFIT: Vagal AF Induction Test. Px: Persistent AF; Ps: Paroxysmal AF; LA: Left atrium size; EF: Ejection fraction; WP: Wenckebach’s point; SNRT: Sinus node recovery time; IACT: Intra-atrial conduction time; EARP: Atrial refractory period, AVRP: Atrioventricular refractory period; IQR: Inter Quartile Range. Parameter VAFIT-negative VAFIT-positive p Number 89 53 Recurrence, N/% 5 (5.6%) 10 (18.7%) 0.012 AF, N/% Px 75 (84.3%) 38 (71.7%) 0.108 Ps 14 (15.7%) 15 (28.3%) Sex, N/% F 30 (33.7%) 11 (20.8%) 0.152 M 59 (66.3%) 42 (79.2%) Age, (y), Median[IQR] 56.5 [48.9-67.0] 59.0 [49.5-70.2] 0.260 Weight, (kg) Median[IQR] 83.4 [72.0-91.0] 78.5 [71.5-90.2] 0.513 Months, Median[IQR] 13.0 (10.0-20.0) 14.0 (7.0-20.0) 0.413 LA, Mean ± SD 38.5 ± 5.0 38.6 ± 5.1 0.646 EF, Median [IQR] 64.0 [63.0-68.2] 63.0 [62.0-68.0] 0.354 HR pre, Median[IQR] 62.0 [54.0-70.0] 60.0 [52.8-68.0] 0.325 HR post, Mean ± SD 75.8 ± 3.0 75.0 ± 12.3 0.715 HR post 1 year, Mean ± SD 69.2±12 65.7±13 0.09 WP, Median[IQR] 157.0 [139.5-173.2] 152.0 [141.8-165.5] 0.316 SNRT, Median[IQR] 1355.5 [1210.0-1622.2] 1392.5 [1299.8-1552.0] 0.54 ARP, Median[IQR] 240.0 [240.0-280.0] 245.0 [228.5-320.0] 0.68 CHA 2 DS 2 -Vasc, Median[IQR] 1.0 [1.0-2.0] 2.0 [1.0-3.0] 0.05 Radioscopy time, Median[IQR] 10.8 [7.9-12.5] 10.3 [8.0-12.0] 0.868 Proc duration, Median[IQR] 3.0 [3.0-3.1] 3.0 [3.0-3.6] 0.261 Complications No complications requiring surgical intervention occurred. Nine cases of inguinal hematoma at the puncture site, two arteriovenous fistula, and one transitory phrenic palsy were clinically solved with short hospitalization delay. Discussion Despite PVI being the gold standard in AF ablation 10 recurrence may reach 50% over 2 to 3 years 11 , 12 . In the original study of CNA5, beyond the good outcome in functional bradyarrhythmias, it was observed an interesting positive effect of CNA on AF ablation15, 13 , 14 . However, at that time, there was no specific endpoint to rationally apply CNA in AF ablation. In the current study, based on the inception of the ECVS in 20152, we are not only reinforcing the initial observations from 20055 but also demonstrating that a negative VAFIT may serve as a valuable endpoint for predicting improved outcomes in AF ablation. Conversely, a positive VAFIT at the end of the procedure is strongly associated with a higher recurrence rate of AF, Figure 4, p=0.012. Considering that the denervation of the atrial walls is proportional to the number of AF-Nests ablated 15,16,17,18 , it can be inferred that after PVI, if the VAFIT remains positive, the CNA could be extended to achieve a negative VAFIT at the operator’s discretion, aiming to reduce long-term recurrences28, Figure 4. Additionally, the multivariable analysis showed no significant other differences, probably due to the relatively healthy patients selected for the study. Elimination of Vagal Effect by CNA A standard endpoint for CNA is the abolition of the vagal response in both the sinus and AV nodes guided by ECVS2. However, given anatomical variations and other intervening factors, a reduction of at least 90% in vagal effects (sinus pause and/or AV block duration) is often deemed adequate, as achieving total denervation may not be feasible in every case28. Notably, denervation of the sinus and AV nodes can occur while significant residual innervation of the atrial wall persists. Furthermore, significant vagal effect may persists after PVI, Figure 3-B,D. This suboptimal outcome may retain a considerable link to AF recurrence 19 , 20 , 21 , 22 . In this study, we observed that the cohort undergoing CNA with vagal effect elimination at all three domains – sinus, AV node, and atrial wall – exhibited a marked decrease in AF recurrence when compared to the group with residual vagal effects reflected by VAFIT-positive, Figure 4, p=0.012. Effect of Cardioneuroablation on Atrial Fibrillation Ablation Numerous studies have indicated that PVI AF ablation leads to a certain degree of denervation and, it seems, that the greater the denervation, the better the outcome 23 , 24 , 25 , 26 . Typically, PVI reduces the degree of vagal response, yet a significant vagal effect induced by ECVS may persists post-PVI, Figure 3-B,D. The denervation by PVI is due to elimination of numerous AF-Nests in the PV antrum, which are indirectly ablated by various PVI techniques. However, CNA controlled by ECVS is the election method to achieve complete vagal effect elimination17, 27 and the denervation of atrial walls is the most critical domain for this endpoint, Figure 3-E, Figure 5-B, and Table 1. The addition of CNA controlled with ECVS has a remarkable impact on PVI resulting in a substantial reduction in recurrence compared to PVI alone 28 . Certainly, this technique could be further enriched with additional tests using isoproterenol and adenosine, particularly for detecting non-PV triggers, as it is likely that the VAFIT-positive group would be reduced with the identification and elimination these additional triggers. 29 Nevertheless, specific denervation endpoint of the atrial walls using CNA with ECVS has not been described. The VAFIT protocol can be a tool to measure the vagal effect on the atrial wall before and after any AF ablation technique. The electrophysiologist can utilize this parameter to pursue an additional endpoint and to have another predictive parameter for long-term outcomes. Naturally, replicating these findings in further studies is mandatory to solidify these conclusions. A fundamental aspect in real-world practice is the training of operators to perform CNA. Typically, since they are already highly skilled in AF ablation, assimilating the CNA technique has been relatively straightforward. However, the key fundamental tool is the ECVS, as this resource allows operators to evaluate the progression of denervation, refining their expertise with each procedure and facilitating the comparison of results across various techniques and centers. Assessment of Atrial Wall Denervation Following Cardioneuroablation Beyond the sinus and AV node denervation, evaluating the extent of denervation in the atrial walls following CNA is challenging. The current study aims to propose a practical measurement for this parameter by using PAS under baseline and during ECVS2. ECVS typically causes a significant reduction in the EARP (Figure 6), and interestingly, an extra stimulus shorter than baseline EARP under ECVS elicits AF induction before CNA, Figure 2-B, Figure 3-D, and Figure 5-A. This observation forms the basis of the VAFIT proposed in this study, a tool for measuring the innervation on the atrial walls. Before ablation, VAFIT typically induces AF, Figure 2-B, and Figure 5-A. However, after CNA with significant denervation, VAFIT usually becomes negative, no longer triggering AF, which indicates the elimination of the vagal effect in the atrial wall. Despite some degree of denervation, after PVI only, VAFIT may continue positive when significant vagal innervation persists, Figure 3-D. However, Figure 4 shows that a VAFIT-negative status would be better as it significantly correlates with AF recurrence reduction. In this study, all cases underwent denervation. However, those achieving a VAFIT-negative post-ablation had a 4.56-fold reduction in recurrence, indicating that the degree of vagal denervation, specifically in the atrial walls, is highly correlated with the long-term success of AF ablation, Figure 4. Remarkable Atrial Refractoriness Modification by Vagal Effect and by CNA As a collateral observation, Figure 6 summarizes atrial refractoriness with ECVS and CNA. Before ablation, only a slight refractory dispersion is observed between the atria (Figure 6-C, 1A-1B). However, during ECVS, there is a profound reduction in EARP (Figure 6, 2A-2B), resulting in a remarkable refractory dispersion (Figure 6-D, 2A-2B), which triggers the AF induction by a single extra stimulus with a coupling interval shorter than the baseline EARP featuring the VAFIT-positive status. Following CNA, a drastic change toward normalization is observed (Figure 6-E, 3A-3B). Thus, CNA not only tends to increase the EARP of the atrial walls (Figure 6-3A-3B) but, more critically, it may eliminate the vagally induced refractory dispersion (Figure 6-D versus E), evidenced by the absence of a refractoriness vagal response. This leads to a marked enhancement of atrial electrical stability, demonstrated by the VAFIT-positive status shifting to negative. Left Atrium Refractoriness Behavior As AF ablation is more extensive in the LA, it often results in more pronounced LA vagal denervation, which can manifest as an EARP increase post-PVI+CNA compared to the basal EARP, likely attributable to a decrease in LA basal vagal tone (Figure 6, 1B versus 3B). Conversely, the RA undergoes less extensive ablation, potentially leading to a modest increase in interatrial refractoriness dispersion, Figure 6-E. However, this change was not statistically significant (Figure 6, C vs E, p=0.051) and could be mitigated by further AF-Nests ablation in the RA if needed. Still considering Figure 6, it is essential to note that the refractory dispersion in E is different from C, as C is dynamic and transitions to D under vagal influence. In contrast, no such vagal effect persists post-CNA, rendering the E dispersion static and invariant, thereby considerably safer than the pre-CNA condition C. These data suggest that vagal denervation is one cornerstone of AF ablation, and that implementing vagal denervation via CNA during PVI may significantly benefit the patient28. Consequently, we consider PVI and CNA complementary methods in AF ablation. The latter can be easily achieved using the classic CNA technique controlled by ECVS, which involves anatomical mapping and ablation of AF-Nests if necessary. Furthermore, the VAFIT protocol may be a useful reproducible electrophysiological endpoint for reducing recurrences. Vagal Induced Refractory Dispersion Acetylcholine causes an intense potassium efflux, immediate hyperpolarization, and reduction in the action potential duration and refractoriness. Unlike skeletal muscle, which has a motor endplate that prevents acetylcholine dispersion in a close model, the atrial myocardium has a non-specialized open neuro-myocardial junction featured by AF-Nests, Figure 7. This allows for heterogeneous acetylcholine diffusion, Figure 7-A and C. As a result, neighboring cells experience abrupt and vast differences in acetylcholine concentration, causing a significant and sudden refractory dispersion, Figure 7-B and C, that easily triggers AF. This supports the VAFIT concept and accounts for the significant reduction in post-PVI recurrence when combined with CNA, which includes wide denervation of the atrial wall. Limitations While providing novel insights into the efficacy of VAFIT-negative status as an endpoint for AF ablation, this study carries certain limitations that warrant consideration. Despite indicating a substantial reduction in AF recurrence, a longer follow-up should be considered. Highly selected patients with a low degree of heart disease may not accurately represent real-world populations. Single-center study could introduce a selection bias and limit the generalizability of the findings. Although ECVS may be easily performed with neurological stimulators, the ECVS may limit the availability in some centers. The use of extra stimuli to induce AF may not replicate the natural onset of AF in some patients, which could potentially skew the results. Technical aspects of this technique depend on a minimal learning curve to get reliable and reproducible results. Another limitation is that VAFIT was performed only at baseline and after completion of the whole procedure (PVI+CNA). Therefore, separate effects of PVI and CNA were not explicitly evaluated despite VAFIT-positive was observed in several patients after PVI. Further research with a larger, multi-center cohort and a longer follow-up are necessary to validate the conclusions and ensure the reproducibility of the VAFIT-negative endpoint in broader clinical practice. Conclusion By achieving a negative VAFIT (Vagal AF Induction Test) status, cardioneuroablation plus PVI successfully reduced AF recurrence by 4.5-fold. Moreover, this approach effectively eliminated the massive atrial refractory dispersion sharply induced by vagal effects. Thus, achieving a VAFIT-negative status seems to be an useful and rational endpoint in AF ablation. The specific validation of atrial wall denervation through extra-cardiac vagal stimulation and programmed atrial stimulation was crucial to these outcomes. Abbreviation AF Atrial Fibrillation AF-Nest Atrial Fibrillation Nests (poorly connected myocardium spots) APS Atrial Programmed Stimulation AT Atrial Tachycardia AV Atrioventricular AVB Atrioventricular Block bpm beats per minute CNA Cardioneuroablation EARP Effective Atrial Refractory Period ECVS Extra-Cardiac Vagal Stimulation EF Ejection Fraction GP Ganglionated Plexus HR Heart Rate IQR Interquartile range LA Left atrium PAS Programmed Atrial Stimulation Ps Persistent Px Paroxysmal PVI Pulmonary Vein Isolation PV Pulmonary Vein SD Standard Deviation VAFIT Vagal Atrial Fibrillation Induction Test References Santangeli P, Zado ES, Garcia FC, Riley MP, Lin D, Frankel DS, Supple GE, Schaller RD, Dixit S, Callans DJ, Marchlinski FE. Lack of prognostic value of atrial arrhythmia inducibility and change in inducibility status after catheter ablation of atrial fibrillation. Heart Rhythm. 2018 May;15(5):660-665. doi: 10.1016/j.hrthm.2017.10.023. 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Pachon-M EI, Pachon-Mateos JC, Higuti C, Santillana-P TG, Lobo T, Pachon C, et al. Relation of Fractionated Atrial Potentials with the Vagal Innervation Evaluated by Extracardiac Vagal Stimulation during Cardioneuroablation. Circulation: Arrhythmia and Electrophysiology 2020:302–313. doi:10.1161/CIRCEP.119.007900. Arruda M, Natale A. Ablation of permanent AF - Adjunctive strategies to pulmonary veins isolation: Targeting AF NEST in sinus rhythm and CFAE in AF. Journal of Interventional Cardiac Electrophysiology 2008;23:51–57. doi:10.1007/S10840-008-9252-Z. Kang KW, Kim TH, Park J, Uhm JS, Joung B, Hwang C, Lee MH, Pak HN. Long-term changes in heart rate variability after radiofrequency catheter ablation for atrial fibrillation: 1-year follow-up study with irrigation tip catheter. J Cardiovasc Electrophysiol. 2014 Jul;25(7):693-700. doi: 10.1111/jce.12398. Epub 2014 Mar 28. PMID: 24575794. Olgin JE, Sih HJ, Hanish S, Jayachandran JV, Wu J, Zheng QH, Winkle W, Mulholland GK, Zipes DP, Hutchins G. Heterogeneous atrial denervation creates substrate for sustained atrial fibrillation. Circulation. 1998 Dec 8;98(23):2608-14. doi: 10.1161/01.cir.98.23.2608. PMID: 9843470. Drexler M, Blum T, Heinroth KM, Hartkopf T, Plehn A, Schirdewahn P, Sedding DG. Heart rate variability as a predictor of successful catheter-guided pulmonary vein isolation for atrial fibrillation. Herz. 2024 Mar;49(2):147-154. doi: 10.1007/s00059-023-05201-6. Epub 2023 Aug 17. PMID: 37589750; PMCID: PMC10917838. Călburean PA, Osorio TG, Sorgente A, Almorad A, Pannone L, Monaco C, Miraglia V, Al Housari M, Mojica J, Bala G, Bisignani A, Lipartiti F, Strazdas A, Ramak R, Overeinder I, La Meir M, Ströker E, Brugada P, Boveda S, Paparella G, Iacopino S, Sieira J, Chierchia GB, de Asmundis C. High vagal tone predicts pulmonary vein reconnection after cryoballoon ablation for paroxysmal atrial fibrillation. Pacing Clin Electrophysiol. 2021 Dec;44(12):2075-2083. doi: 10.1111/pace.14408. Epub 2021 Nov 26. PMID: 34773413. Katritsis DG, Pokushalov E, Romanov A, Giazitzoglou E, Siontis GCM, Po SS, et al. Autonomic denervation added to pulmonary vein isolation for paroxysmal atrial fibrillation: a randomized clinical trial. J Am Coll Cardiol 2013;62:2318–2325. Liao TE, Li CH, Lin YJ, Chang SL, Hu YF, Chung FP, Chao TF, Liao JN, Yang HW, Lo MT, Chen SA, Lo LW. Fractal complexity alternations in paroxysmal atrial fibrillation patients with and without recurrence after pulmonary vein isolation. Ann Noninvasive Electrocardiol. 2023 Sep;28(5):e13074. doi: 10.1111/anec.13074. Epub 2023 Jul 19. PMID: 37469220; PMCID: PMC10475888. Zhang E, Liang S, Sun T, Xu J, Lu F, Wu D, Zhang J, He L, Zhang F, Fan S, Ma W. Prognostic value of heart rate variability in atrial fibrillation recurrence following catheter ablation: A systematic review and meta-analysis. Front Cardiovasc Med. 2023 Feb 2;9:1048398. doi: 10.3389/fcvm.2022.1048398. PMID: 36818913; PMCID: PMC9932203. Kampaktsis PN, Oikonomou EK, Y. Choi D, Cheung JW. Efficacy of ganglionated plexi ablation in addition to pulmonary vein isolation for paroxysmal versus persistent atrial fibrillation: a meta-analysis of randomized controlled clinical trials. Journal of Interventional Cardiac Electrophysiology 2017;50:253–260. doi:10.1007/s10840-017-0285-z. Sarabanda AV, Melo SL, Rivarola E, Hachul D, Scanavacca M. Anatomically guided atrial ganglionated plexus ablation evaluated by extracardiac vagal stimulation for vagally mediated atrioventricular block. HeartRhythm Case Rep. 2021 Feb 10;7(5):301-305. doi: 10.1016/j.hrcr.2021.02.002. PMID: 34026520; PMCID: PMC8134772. Pachon-M EI, Clark J, Lobo TJ, Pachon CT, Higuti C, Pachon MZ, Ortencio F, Amarante RC, Osorio TG. Impact of Cardioneuroablation with Vagal Denervation Confirmed by Vagus Nerve Stimulation on Pulmonary Vein Isolation for Atrial Fibrillation Catheter Ablation. Journal of Atrial Fibrillation & Electrophysiology. 2023 Nov 1;16(8). Elayi CS, Di Biase L, Bai R, Burkhardt JD, Mohanty P, Santangeli P, Sanchez J, Hongo R, Gallinghouse GJ, Horton R, Bailey S. Administration of isoproterenol and adenosine to guide supplemental ablation after pulmonary vein antrum isolation. Journal of cardiovascular electrophysiology. 2013 Nov;24(11):1199-206. Additional Declarations The authors declare no competing interests. Supplementary Files VAFITJICEPachon.mp4 Vagal AF Induction Test (VAFIT): A New Endpoint for Optimizing Atrial Fibrillation Ablation through Cardioneuroablation Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-5643881","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":390292395,"identity":"4c4e6766-75f6-4b75-8d2d-bdcdd62c35bc","order_by":0,"name":"JC Pachon-M","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAnklEQVRIiWNgGAWjYHACNiC2gTGI15JGupbDJGgxZz/87MHHHecT589uYHtcQYwWy540c8OZZ24nbrhzgN3wDDFaDA7ksEnztgG1SCSwSTYQpeX8G5CWc4nzZxCt5QbYlgOJDTeI1WI545mZ5My2ZOMNdw62GxKlxZw/+ZnExzY72fmzm489JM5hcJYEI1EaULQQp2EUjIJRMApGIAAAgv4yLn46DPIAAAAASUVORK5CYII=","orcid":"https://orcid.org/0000-0002-5111-488X","institution":"Sao Paulo University, Sao Paulo Heart Hospital","correspondingAuthor":true,"prefix":"","firstName":"JC","middleName":"","lastName":"Pachon-M","suffix":""},{"id":390292396,"identity":"0185d545-2406-4e6c-8bdc-d4ffa85bbb66","order_by":1,"name":"Enrique I Pachon-M","email":"","orcid":"","institution":"Sao Paulo University, Sao Paulo Heart Hospital","correspondingAuthor":false,"prefix":"","firstName":"Enrique","middleName":"I","lastName":"Pachon-M","suffix":""},{"id":390292397,"identity":"0200de6b-120b-4a98-97dc-1fb90ba7324e","order_by":2,"name":"Tomas G santillana-P","email":"","orcid":"","institution":"Sao Paulo Heart Hospital","correspondingAuthor":false,"prefix":"","firstName":"Tomas","middleName":"G","lastName":"santillana-P","suffix":""},{"id":390292398,"identity":"9b8c47fb-d61e-4217-ab15-aa932b0db14b","order_by":3,"name":"Tasso J Lobo","email":"","orcid":"","institution":"Sao Paulo Heart Hospital","correspondingAuthor":false,"prefix":"","firstName":"Tasso","middleName":"J","lastName":"Lobo","suffix":""},{"id":390292399,"identity":"e787a9a7-2042-4598-9a51-4d024fb4adb7","order_by":4,"name":"Carlos T Cunha-P","email":"","orcid":"","institution":"Sao Paulo Heart Hospital","correspondingAuthor":false,"prefix":"","firstName":"Carlos","middleName":"T","lastName":"Cunha-P","suffix":""},{"id":390292400,"identity":"bf7db0cf-0dc1-4839-8a72-83effd11d8b9","order_by":5,"name":"Juan Carlos Pachon-M","email":"","orcid":"","institution":"Sao Paulo University, Sao Paulo Heart Hospital","correspondingAuthor":false,"prefix":"","firstName":"Juan","middleName":"Carlos","lastName":"Pachon-M","suffix":""},{"id":390292401,"identity":"0f260283-8129-448f-a0cf-197670c31cd5","order_by":6,"name":"Maria Zelia Cunha-P","email":"","orcid":"","institution":"Sao Paulo Heart Hospital","correspondingAuthor":false,"prefix":"","firstName":"Maria","middleName":"Zelia","lastName":"Cunha-P","suffix":""},{"id":390292402,"identity":"fa48a2ac-8989-48e1-b9cc-8a6405cedf93","order_by":7,"name":"John Clark","email":"","orcid":"","institution":"Akron Children's Hospital","correspondingAuthor":false,"prefix":"","firstName":"John","middleName":"","lastName":"Clark","suffix":""}],"badges":[],"createdAt":"2024-12-14 13:53:55","currentVersionCode":1,"declarations":{"humanSubjects":false,"vertebrateSubjects":false,"conflictsOfInterestStatement":false,"humanSubjectEthicalGuidelines":false,"humanSubjectConsent":false,"humanSubjectClinicalTrial":false,"humanSubjectCaseReport":false,"vertebrateSubjectEthicalGuidelines":false},"doi":"10.21203/rs.3.rs-5643881/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-5643881/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":72204780,"identity":"251e3ca2-45f8-4ce6-89a9-dd8631e1112e","added_by":"auto","created_at":"2024-12-23 16:27:25","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":260670,"visible":true,"origin":"","legend":"\u003cp\u003eMethodology of cardioneuroablation. A: Extra-Cardiac Vagal Stimulation (ECVS); A1: Customized Neurostimulator or Electromyograph; A2: ECVS within the internal jugular vein causes asystole Pre-CNA and no vagal response Post-CNA; B: Anatomical localization of the 4 main Ganglionated Plexi (GPs); C: Conventional mapping of AF-Nests with filter adjustments in time domain; D: Spectral Analysis of an AF-Nest (frequency domain); E; F; G: Electroanatomic Model displaying GP and AF-Nest areas through Fractionation Mapping.\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-5643881/v1/994dacc719e58981eee4058e.png"},{"id":72204784,"identity":"5509ae48-668c-4e04-8704-2d532b143e7c","added_by":"auto","created_at":"2024-12-23 16:27:26","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":209534,"visible":true,"origin":"","legend":"\u003cp\u003eExample of the Vagal AF Induction Test (VAFIT). A: Under basal conditions, the EARP was measured using the conventional method; it was 260ms, and AF was not induced. B: However, during vagal stimulation (ECVS), remeasurement of EARP induced AF with only one extra stimulus as early as 80ms resulted in a VAFIT-positive status. Additionally, there is high-grade AV block resulting from the ECVS before CNA; C: Following CNA, EARP remeasurement during ECVS resulted in 250ms, there is no more vagal-induced EARP reduction, and no longer AF was induced, confirming a VAFIT-negative status. Additionally, no more AV block was induced post-CNA due to vagal effect elimination. Thus, in this example, the patient shifted from a VAFIT-positive status in B to a VAFIT-negative status in C post-CNA. ECVS: Extra-Cardiac Vagal Stimulation.\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-5643881/v1/86a61c620546c607f3bd8a22.png"},{"id":72206467,"identity":"877a08df-74f9-48b7-9eac-88cd1df805ec","added_by":"auto","created_at":"2024-12-23 16:43:26","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":292444,"visible":true,"origin":"","legend":"\u003cp\u003eVagal Innervation Assessment with ECVS. A: Baseline ECVS showing high vagal effect with a sinus pause of 9 seconds. B: Post-PVI, the ECVS indicates reduced innervation with the sinus pause decreasing to 5.3 seconds, yet significant vagal effect persists; C: Post-PVI+CNA: the ECVS demonstrates complete vagal response elimination, indicating denervation; D: Atrial wall vagal innervation assessment: Even post-PVI there is enough vagal innervation to keep VAFIT-positive. In this case, despite a baseline EARP of 280ms, an extra stimulus during ECVS as short as 100ms ECVS elicits a response and induces AF; E: Following ablation with PVI+CNA, EARP during ECVS increases to 240ms and no longer triggers AF, achieving VAFIT-negative status.\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-5643881/v1/8c32bdb6cc248a8738044f33.png"},{"id":72205339,"identity":"f30cec89-c210-49bc-85af-ea74b7a1366b","added_by":"auto","created_at":"2024-12-23 16:35:26","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":116655,"visible":true,"origin":"","legend":"\u003cp\u003eSurvival curves and Hazard-Ratio by VAFIT Status. These Kaplan-Meier curves delineates the survival probabilities over time for two patient cohorts categorized by VAFIT status upon completion of the PVI+CAN procedure. The blue curve depicts patients with a negative VAFIT status, signifying no inducible AF by extrastimulus, while the red curve represents patients with a positive VAFIT status, indicating AF was still inducible after the procedure. On the right, the Hazard-Ratio plot indicates an increase in risk for the VAFIT-positive group, HR = 4.56 (1.37-15.23, p=0.014), implying a significantly higher probability of AF recurrence than the VAFIT-negative cohort. The HR, derived from a multivariate Cox proportional hazards model, highlights the prognostic importance of VAFIT status in patients undergoing AF ablation with CNA. The HR illustrates that a VAFIT-positive status significantly correlates with AF recurrence risk, while other factors do not show a significant association in this analysis.\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-5643881/v1/318fed3200a86ba2eac89296.png"},{"id":72206468,"identity":"4b3269c8-8ae4-4b85-bbf2-de865a4c59df","added_by":"auto","created_at":"2024-12-23 16:43:26","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":172712,"visible":true,"origin":"","legend":"\u003cp\u003eIn this patient, the baseline EARP of the LA was 220ms. With the vagal effect induced by ECVS, there is a significant reduction in the EARP, making it possible to obtain an atrial response in the form of AF with only 80ms (VAFIT-positive). This response demonstrates the extreme effect of vagal action on reducing the EARP and the consequent electrical instability of the atrial walls, not only by reducing the EARP but also by increasing the refractoriness dispersion, Figure 6-C. After PVI with CNA, vagal denervation was achieved, preventing the EARP shortening, and an extra stimulus in the LA with 260ms is conducted with delay, another with 240ms is blocked (EARP), and no longer AF is induced (VAFIT-negative). The EARP recovered the basal pre-ablation value showing no longer reduction during vagal stimulation. In the upper tracing, a 2:1 AV block during atrial pacing followed by AF with a high degree of AV block are observed due to the vagal effect on the AV node. These effects no longer occurred in the lower tracing because of the CNA denervation.\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-5643881/v1/4beaf584b5cd1fc1ca4f2329.png"},{"id":72204794,"identity":"dd57cc35-8a1c-4fd5-bbea-b2a262c1fc54","added_by":"auto","created_at":"2024-12-23 16:27:26","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":100566,"visible":true,"origin":"","legend":"\u003cp\u003eStudy of atrial refractoriness by PAS and ECVS; 1: baseline, 2: Pre-PVI+CNA during ECVS, and 3: Post-PVI+CNA during ECVS; The EARP is drastically reduced by the vagal effect: 1A-1B vs 2A-2B. Also, the slight interatrial basal refractoriness dispersion (C) drastically increases with vagal stimulation (D). This effect is strongly associated with the induction of AF by a single extra stimulus in all cases (VAFIT positive) before CNA. CNA increases the basal atrial refractory period: 1A-1B vs 3A-3B, reduces refractoriness dispersion: D versus E, and prevents reinduction of AF with PAS + vagal stimulation at the end of the procedure: 2A-2B vs 3A-3B (VAFIT negative).\u003c/p\u003e","description":"","filename":"6.png","url":"https://assets-eu.researchsquare.com/files/rs-5643881/v1/a6cff38fbe8d8dd8fef61c0d.png"},{"id":72204790,"identity":"857c3944-54a0-463e-b6af-872633540852","added_by":"auto","created_at":"2024-12-23 16:27:26","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":334492,"visible":true,"origin":"","legend":"\u003cp\u003eAtrial Myocardium and Acetylcholine-mediated refractoriness dispersion. The acetylcholine (ACh) diffusion in the AF-Nest sites, an open model of innervation, markedly and suddenly promotes refractory dispersion (A versus C to B versus C). In some cases, the ECVS can reduce the EARP from 280ms to 80ms in highly innervated cells while minimally affecting less innervated cells. This heterogeneity in refractoriness facilitates AF induction by creating substantial electrical potential differences across adjacent cells, leading to a VAFIT-positive status.\u003c/p\u003e","description":"","filename":"7.png","url":"https://assets-eu.researchsquare.com/files/rs-5643881/v1/12cbe90cbf623afbfff23f5a.png"},{"id":72205340,"identity":"9139d233-f926-4da3-9d8b-9e4dba1e90c3","added_by":"auto","created_at":"2024-12-23 16:35:26","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":87284,"visible":true,"origin":"","legend":"\u003cp\u003eUnnumbered image in the Methods section.\u003c/p\u003e","description":"","filename":"UnnumberFig.png","url":"https://assets-eu.researchsquare.com/files/rs-5643881/v1/cc040e41128b5f9f6832e6d4.png"},{"id":72617222,"identity":"dc304f63-b949-4a82-acb1-3d1f930410b1","added_by":"auto","created_at":"2024-12-30 11:57:12","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2020969,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-5643881/v1/ebf5ad52-bcd0-4d93-b611-f5be3a9c354c.pdf"},{"id":72204809,"identity":"cc01d167-1799-4c7d-b4bd-a1bfe6a845c0","added_by":"auto","created_at":"2024-12-23 16:27:27","extension":"mp4","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":37561610,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eVagal AF Induction Test (VAFIT): A New Endpoint for Optimizing Atrial Fibrillation Ablation through Cardioneuroablation\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"VAFITJICEPachon.mp4","url":"https://assets-eu.researchsquare.com/files/rs-5643881/v1/c0e69da8c2b54a3a98216d14.mp4"}],"financialInterests":"The authors declare no competing interests.","formattedTitle":"\u003cp\u003e\u003cstrong\u003eVagal AF Induction Test (VAFIT): A New Endpoint for Optimizing Atrial Fibrillation Ablation through Cardioneuroablation\u003c/strong\u003e\u003c/p\u003e","fulltext":[{"header":"Introduction","content":"\u003cp\u003eDespite significant advancements, a functional endpoint for AF ablation has yet to be established\u003csup\u003e1\u003c/sup\u003e. Inducing AF with a single extra stimulus in the EP lab is very rare. Furthermore, it would be remarkable if a single extra stimulus during the EARP could trigger any atrial activity, let alone induce atrial fibrillation. However, we found that a single extra stimulus, applied under vagal action by ECVS during the basal value of EARP, can elicit atrial responses and induces AF in virtually all patients \u0026ndash; Vagal AF Induction Test: VAFIT positive. This response is suppressed by CNA, which can successfully convert a positive VAFIT to negative. In this article, we will investigate whether achieving a negative VAFIT at the conclusion of AF ablation via CNA impacts long-term recurrence rates.\u003c/p\u003e\n\u003cp\u003eThe aim of this article is to study the long-term recurrence following AF ablation through PVI combined with CNA, comparing groups that concluded the procedure with a VAFIT-positive versus VAFIT-negative status.\u0026nbsp;\u003c/p\u003e"},{"header":"Methods","content":"\u003cp\u003eA prospective cohort study involving 142 patients, including 101(71.1%) males with a mean age of 57.5 [48.9-70.2]years, with symptomatic AF, either paroxysmal (79.6%) or persistent (20.4%), refractory to medication, and without significant heart disease. The mean LA size was 38.0[35.0-41.2]mm, and the EF was 0.63[0.62-0.68]. Patients underwent PVI and CNA by RF catheter ablation, with denervation success confirmed by ECVS. The cohort was followed for up to 40 months (5 to 40 with median of 15 months) to monitor AF recurrence, comparing those with negative versus positive VAFIT.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics Declaration\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study was conducted as part of our regular clinical application of ablation treatments approved for patients treated at our hospital. Each patient provided written informed consent before treatment following a detailed in-person interview that thoroughly explained the procedure\u0026rsquo;s objectives, potential risks, and benefits. The study fully adhered to the ethical principles outlined in the Declaration of Helsinki, ensuring the protection of the rights, safety, and well-being of the patients. Robust measures were implemented to safeguard the patients\u0026rsquo; safety and data collected during the study in compliance with local regulatory requirements and international ethical standards.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eInclusion criteria\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eIncluded patients met the following criteria:\u003c/p\u003e\n\u003cp\u003e1. Paroxysmal or persistent AF with episodes lasting \u0026lt; 1 year in accordance with the 2014 AHA/ACC/HRS guidelines\u003csup\u003e7\u003c/sup\u003e.\u003c/p\u003e\n\u003cp\u003e2. Age: 20 to 80 years.\u003c/p\u003e\n\u003cp\u003e3. Refractoriness or impossibility of pharmacological treatment.\u003c/p\u003e\n\u003cp\u003e4. Absence of, or mild, cardiomyopathy and no significant systemic pathology.\u003c/p\u003e\n\u003cp\u003e5. Ability to comply with the written informed consent, with the study, and with the follow-up.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eExclusion Criteria\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThose who met any of the following criteria:\u003c/p\u003e\n\u003cp\u003e1. Previous cardiac surgery or AF ablation.\u003c/p\u003e\n\u003cp\u003e2. AF lasting over 1 year (long-standing AF).\u003c/p\u003e\n\u003cp\u003e3. Valvar disease or cardiomyopathy (EF\u0026lt;50%).\u003c/p\u003e\n\u003cp\u003e4. Left ventricular hypertrophy (wall thickness \u0026gt;15 mm) or coronary artery disease.\u003c/p\u003e\n\u003cp\u003e5. Contraindication to anticoagulants (heparin, warfarin, NOAC).\u003c/p\u003e\n\u003cp\u003e6. LA diameter \u0026gt;55 mm.\u003c/p\u003e\n\u003cp\u003e7. NYHA Heart Failure Class \u0026gt; I, cerebrovascular or important organic or metabolic disease.\u003c/p\u003e\n\u003cp\u003e8. Anatomical impossibility to perform ECVS.\u003c/p\u003e\n\u003cp\u003e9. Current or planned pregnancy.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eExtracardiac Vagal Stimulation (ECVS)\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eECVS was performed without dissection or direct contact with the vagus nerve,\u0026nbsp;Figure 1, following the original technique\u003csup\u003e2\u003c/sup\u003e. An EP lead was advanced through the superior vena cava and internal jugular vein up to the right jugular foramen, Figure 1-A), usually the closest location to the vagus nerve. ECVS was achieved by using a neurostimulator, Figure 1-A1, delivering a pulsed electric field (Amplitude of 1V/kg body weight up to 70V, pulse width of 50 microseconds, at a frequency of 50Hz for 5 seconds) within the jugular vein. The typical response includes transient asystole and/or AV block, Figure 1-A2. Additionally, the VAFIT protocol was implemented, as detailed below. ECVS was performed prior to ablation to assess the basal response, during the procedure to guide denervation progress, and at the end of the procedure to confirm the endpoint.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethodology for VAFIT: Vagal Atrial Fibrillation Induction Test\u0026nbsp;\u003c/strong\u003e(see video)\u003c/p\u003e\n\u003cp\u003eThe EARP was determined at baseline on the antero-lateral right atrium and in the posterior left atrium by coronary sinus, Figure 2-A. It was then reassessed during ECVS, starting at a coupling interval of 80ms and increasing by 20ms at each step until capture occurred. Induction of AF was classified as VAFIT-positive, Figure 2-B, and its absence as VAFIT-negative, Figure 2-C. Following CNA, EARP assessment and VAFIT were repeated. Any changes in EARP, VAFIT results, and the presence or absence of arrhythmias were systematically documented.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eRadiofrequency Ablation\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll procedures involved orotracheal intubation, general intravenous anesthesia monitored by BIS Spectral Monitoring System, Medtronic, Minneapolis, MN, USA, and transesophageal echocardiography. Parasympatholytic drugs were withheld for the last two days prior to the procedure. A conventional recorder and the NAVX-Ensite\u0026reg; Velocity/Precision Cardiac Mapping System, Abbott, IL, USA were employed. RF Catheter was guided by 3D electroanatomic mapping supplemented with fluoroscopy through the femoral vein using the Seldinger technique. A duodecapolar catheter was positioned in the coronary sinus, and the LA was accessed via transseptal puncture. HD-Grid or a decapolar circular catheter Abbott, IL, USA was used to create 3D anatomical models and a fractionation map simultaneously. Conventional PVI\u003csup\u003e3,4\u003c/sup\u003e proceeded using the Abbott\u0026nbsp; FlexAbility Ablation Catheter with 40W/42\u003csup\u003eo\u003c/sup\u003eC/17ml/minute. An activated clotting time of 300 to 400 seconds was maintained with an intravenous heparin infusion.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCardioneuroablation\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAfter PVI, stepwise CNA was performed targeting the P-area17\u0026nbsp;(Figure 1-F), the four main ganglionated plexi (Figure 1-B, E, F, G), and AF-Nests\u003csup\u003e5\u003c/sup\u003e,\u003csup\u003e6\u003c/sup\u003e,16,\u003csup\u003e7\u003c/sup\u003e including the Marshall\u0026rsquo;s vein area\u003csup\u003e8\u003c/sup\u003e, (Figure 1-C,D), in both atria aiming to achieve either complete elimination or significant attenuation of the vagal effect\u003csup\u003e9\u003c/sup\u003e. The P area is a region of the left interatrial septum between the insertion of the right PVs, the LA roof, and the fossa ovalis. Typically, ablation of this area causes the greatest denervation of P cells. Interestingly, it corresponds to the area of the ancient Ludwig ganglion described in amphibians in the 19th century17,28. If necessary, additional AF-Nests were identified using filtered recordings (300-500Hz,\u0026nbsp;Figure 1-C) and/or fractionation mapping at the operator\u0026rsquo;s discretion, Figure 1-E,F,G, until the elimination or significant attenuation of the vagal effect.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEndpoint\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe PVI endpoint was the conventional PV isolation. The CNA endpoint (denervation) was the elimination or 90% attenuation of the vagal response by ECVS,\u0026nbsp;Figure 1-A2 and Figure 3-C. The denervation criteria are shown in\u0026nbsp;Table 1. Given the wide vagal innervation throughout the atrium, the protocol included denervation criteria across three distinct vagal innervation domains:\u003c/p\u003e\n\u003cp\u003eTable\u0026nbsp;1\u0026nbsp;\u0026ndash; Vagal domains identified by ECVS with respective innervation and denervation criteria. AV: Atrioventricular; VAFIT: Vagal AF Induction Test; EARP: Effective Atrial Refractory Period\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"586\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eDomain\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 161px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eProtocol\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 189px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ePre-CNA\u003cbr\u003e\u003c/strong\u003e\u003cstrong\u003eInnervation Criteria\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 151px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ePost-CNA\u003cbr\u003e\u003c/strong\u003e\u003cstrong\u003eDenervation Criteria\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e1. Sinus Node\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 161px;\"\u003e\n \u003cp\u003e1. Basal Sinus Rhythm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 189px;\"\u003e\n \u003cp\u003e1. Sinus Arrest/Pause\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 151px;\"\u003e\n \u003cp\u003e1. Sinus rhythm\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e2. AV Node\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 161px;\"\u003e\n \u003cp\u003e2. Atrial Pacing\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 189px;\"\u003e\n \u003cp\u003e2. AV Block\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 151px;\"\u003e\n \u003cp\u003e2. No AV Block\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"2\" style=\"width: 85px;\"\u003e\n \u003cp\u003e3. Atrial Wall\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" style=\"width: 161px;\"\u003e\n \u003cp\u003e3. EARP measurement + VAFIT\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 189px;\"\u003e\n \u003cp\u003e3. Significant EARP reduction\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 151px;\"\u003e\n \u003cp\u003e3. Abolishment of vagal EARP shortening\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 189px;\"\u003e\n \u003cp\u003e4. VAFIT-positive\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 151px;\"\u003e\n \u003cp\u003e4. VAFIT-negative\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003eFollow-up\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003ePatients were followed for up to 40 months (median of 15[IQR:7-20]) with evaluations at 30, 60, 120 days, and subsequently every six months. They were instructed to document any arrhythmias or symptoms using ECG, Holter monitoring, Kardia device, or smartwatches with ECG, and to immediately transmit the recordings or visit the emergency department if they experienced any sustained arrhythmias. Patients were also encouraged to report any symptoms directly, by phone, email, or through social media. Exercise testing and Holter monitoring were conducted after 3 and 6 months, then annually, and as needed if symptoms occurred. Recurrence was defined as any AF/AT episode lasting more than 30 seconds.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eStatistical analysis\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe Pearson Chi-Squared test and Fisher\u0026rsquo;s exact test were chosen to assess the independence of categorical data between groups. The distribution of continuous variables was evaluated using the Shapiro-Wilk test. Results for continuous variables are reported as mean \u0026plusmn; standard deviation for normally distributed data, and median with interquartile ranges for data not normally distributed, analyzed with non-parametric tests. For continuous variables that assumed a normal distribution but potentially had unequal variances, robust Welch\u0026rsquo;s t-test was employed. The Mann-Whitney U test was used to compare medians of variables that were not normally distributed. Event-free survival rates were estimated using the Kaplan-Meier model, with differences between groups assessed using the log-rank test. Cox regression was utilized for both univariate and multivariate analyses to determine hazard ratios, with the proportional hazard assumption tested for validity. Statistical significance was set at a two-sided p-value of less than 0.05. Data analysis was conducted using SPSS (version 28.0.1.1) and the latest version of Jamovi (2023, Version 2.4.14.0).\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003ePre-ablation ECVS showed significant vagal responses in every case and VAFIT was also positive in all cases. Post-Ablation VAFIT became negative in 89(62.9%) and persisted positive, with sustained or non-sustained AF reinduction, in 53(37.1%) cases. In the initial phase (142 patients), VAFIT was positive, and AF was sustained in 29 cases (20.4%). In the final phase, VAFIT was positive in 53 patients with sustained AF in 4 cases (7.5%), p=0.003.\u003c/p\u003e\n\u003cp\u003eIn the comparison of post-ablation results the VAFIT was negative in 89 and positive in 53 patients. AF recurrence was significantly higher in the VAFIT-positive group (18.7%) compared to the VAFIT-negative group (5.6%, p=0.012). This indicates a statistically significant association between VAFIT-positive status and recurrence of AF post-ablation, HR=4.56(1.37-15.23, p=0.014). Table 2 displays the results and the statistical treatment between the VAFIT-negative and Positive groups. The groups show similar characteristics except for a higher AF recurrence in the VAFIT-positive group, (p=0.012).\u003c/p\u003e\n\u003cp\u003eThese results suggest that in this cohort, while persistent VAFIT-positive status is associated with higher AF recurrence, other demographic and clinical parameters do not appear to differ significantly between both groups, Figure 4 on the right.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eTable\u0026nbsp;2\u0026nbsp;- Clinical and Demographic Parameters between VAFIT-negative and Positive Groups. VAFIT: Vagal AF Induction Test. Px: Persistent AF; Ps: Paroxysmal AF; LA: Left atrium size; EF: Ejection fraction; WP: Wenckebach\u0026rsquo;s point; SNRT: Sinus node recovery time; IACT: Intra-atrial conduction time; EARP: Atrial refractory period, AVRP: Atrioventricular refractory period; IQR: Inter Quartile Range.\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"542\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"2\" style=\"width: 198px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eParameter\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 138px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eVAFIT-negative\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 143px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eVAFIT-positive\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 63px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ep\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"2\" style=\"width: 198px;\"\u003e\n \u003cp\u003eNumber\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 138px;\"\u003e\n \u003cp\u003e89\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 143px;\"\u003e\n \u003cp\u003e53\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 63px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"2\" style=\"width: 198px;\"\u003e\n \u003cp\u003eRecurrence, \u0026nbsp; N/% \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 138px;\"\u003e\n \u003cp\u003e5 (5.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 143px;\"\u003e\n \u003cp\u003e10 (18.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 63px;\"\u003e\n \u003cp\u003e0.012\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"2\" style=\"width: 42px;\"\u003e\n \u003cp\u003eAF, \u0026nbsp; \u0026nbsp; N/%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 156px;\"\u003e\n \u003cp\u003ePx\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 138px;\"\u003e\n \u003cp\u003e75 (84.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 143px;\"\u003e\n \u003cp\u003e38 (71.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" style=\"width: 63px;\"\u003e\n \u003cp\u003e0.108\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 156px;\"\u003e\n \u003cp\u003ePs\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 138px;\"\u003e\n \u003cp\u003e14 (15.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 143px;\"\u003e\n \u003cp\u003e15 (28.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"2\" style=\"width: 42px;\"\u003e\n \u003cp\u003eSex, \u0026nbsp; \u0026nbsp; N/%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 156px;\"\u003e\n \u003cp\u003eF\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 138px;\"\u003e\n \u003cp\u003e30 (33.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 143px;\"\u003e\n \u003cp\u003e11 (20.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" style=\"width: 63px;\"\u003e\n \u003cp\u003e0.152\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 156px;\"\u003e\n \u003cp\u003eM\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 138px;\"\u003e\n \u003cp\u003e59 (66.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 143px;\"\u003e\n \u003cp\u003e42 (79.2%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"2\" style=\"width: 198px;\"\u003e\n \u003cp\u003eAge, (y), Median[IQR]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 138px;\"\u003e\n \u003cp\u003e56.5 [48.9-67.0]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 143px;\"\u003e\n \u003cp\u003e59.0 [49.5-70.2]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 63px;\"\u003e\n \u003cp\u003e0.260\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"2\" style=\"width: 198px;\"\u003e\n \u003cp\u003eWeight, (kg) Median[IQR]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 138px;\"\u003e\n \u003cp\u003e83.4 [72.0-91.0]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 143px;\"\u003e\n \u003cp\u003e78.5 [71.5-90.2]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 63px;\"\u003e\n \u003cp\u003e0.513\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"2\" style=\"width: 198px;\"\u003e\n \u003cp\u003eMonths, \u0026nbsp; \u0026nbsp; Median[IQR]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 138px;\"\u003e\n \u003cp\u003e13.0 (10.0-20.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 143px;\"\u003e\n \u003cp\u003e14.0 (7.0-20.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 63px;\"\u003e\n \u003cp\u003e0.413\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"2\" style=\"width: 198px;\"\u003e\n \u003cp\u003eLA, \u0026nbsp; Mean \u0026plusmn; SD\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 138px;\"\u003e\n \u003cp\u003e38.5\u0026nbsp;\u0026plusmn;\u0026nbsp;5.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 143px;\"\u003e\n \u003cp\u003e38.6\u0026nbsp;\u0026plusmn;\u0026nbsp;5.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 63px;\"\u003e\n \u003cp\u003e0.646\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"2\" style=\"width: 198px;\"\u003e\n \u003cp\u003eEF, \u0026nbsp; \u0026nbsp; Median [IQR]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 138px;\"\u003e\n \u003cp\u003e64.0 [63.0-68.2]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 143px;\"\u003e\n \u003cp\u003e63.0 [62.0-68.0]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 63px;\"\u003e\n \u003cp\u003e0.354\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"2\" style=\"width: 198px;\"\u003e\n \u003cp\u003eHR pre, Median[IQR]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 138px;\"\u003e\n \u003cp\u003e62.0 [54.0-70.0]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 143px;\"\u003e\n \u003cp\u003e60.0 [52.8-68.0]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 63px;\"\u003e\n \u003cp\u003e0.325\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"2\" style=\"width: 198px;\"\u003e\n \u003cp\u003eHR post, Mean\u0026nbsp;\u0026plusmn;\u0026nbsp;SD\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 138px;\"\u003e\n \u003cp\u003e75.8\u0026nbsp;\u0026plusmn;\u0026nbsp;3.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 143px;\"\u003e\n \u003cp\u003e75.0\u0026nbsp;\u0026plusmn;\u0026nbsp;12.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 63px;\"\u003e\n \u003cp\u003e0.715\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"2\" style=\"width: 0px;\"\u003e\n \u003cp\u003eHR post 1 year, Mean\u0026nbsp;\u0026plusmn;\u0026nbsp;SD\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003e69.2\u0026plusmn;12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 0px;\"\u003e\n \u003cp\u003e65.7\u0026plusmn;13\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 0px;\"\u003e\n \u003cp\u003e0.09\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"2\" style=\"width: 198px;\"\u003e\n \u003cp\u003eWP, \u0026nbsp; \u0026nbsp; \u0026nbsp;Median[IQR]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 138px;\"\u003e\n \u003cp\u003e157.0 [139.5-173.2]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 143px;\"\u003e\n \u003cp\u003e152.0 [141.8-165.5]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 63px;\"\u003e\n \u003cp\u003e0.316\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"2\" style=\"width: 198px;\"\u003e\n \u003cp\u003eSNRT, \u0026nbsp;Median[IQR]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 138px;\"\u003e\n \u003cp\u003e1355.5 [1210.0-1622.2]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 143px;\"\u003e\n \u003cp\u003e1392.5 [1299.8-1552.0]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 63px;\"\u003e\n \u003cp\u003e0.54\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"2\" style=\"width: 198px;\"\u003e\n \u003cp\u003eARP, \u0026nbsp; \u0026nbsp; \u0026nbsp;Median[IQR]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 138px;\"\u003e\n \u003cp\u003e240.0 [240.0-280.0]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 143px;\"\u003e\n \u003cp\u003e245.0 [228.5-320.0]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 63px;\"\u003e\n \u003cp\u003e0.68\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"2\" style=\"width: 198px;\"\u003e\n \u003cp\u003eCHA\u003csub\u003e2\u003c/sub\u003eDS\u003csub\u003e2\u003c/sub\u003e-Vasc, \u0026nbsp;Median[IQR]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 138px;\"\u003e\n \u003cp\u003e1.0 [1.0-2.0]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 143px;\"\u003e\n \u003cp\u003e2.0 [1.0-3.0]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 63px;\"\u003e\n \u003cp\u003e0.05\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"2\" style=\"width: 198px;\"\u003e\n \u003cp\u003eRadioscopy time, \u0026nbsp;Median[IQR]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 138px;\"\u003e\n \u003cp\u003e10.8 [7.9-12.5]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 143px;\"\u003e\n \u003cp\u003e10.3 [8.0-12.0]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 63px;\"\u003e\n \u003cp\u003e0.868\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"2\" style=\"width: 198px;\"\u003e\n \u003cp\u003eProc duration, Median[IQR]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 138px;\"\u003e\n \u003cp\u003e3.0 [3.0-3.1]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 143px;\"\u003e\n \u003cp\u003e3.0 [3.0-3.6]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 63px;\"\u003e\n \u003cp\u003e0.261\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003eComplications\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNo complications requiring surgical intervention occurred. Nine cases of inguinal hematoma at the puncture site, two arteriovenous fistula, and one transitory phrenic palsy were clinically solved with short hospitalization delay.\u0026nbsp;\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eDespite PVI being the gold standard in AF ablation\u003csup\u003e10\u003c/sup\u003e recurrence may reach 50% over 2 to 3 years\u003csup\u003e11\u003c/sup\u003e,\u003csup\u003e12\u003c/sup\u003e. In the original study of CNA5, beyond the good outcome in functional bradyarrhythmias, it was observed an interesting positive effect of CNA on AF ablation15,\u003csup\u003e13\u003c/sup\u003e,\u003csup\u003e14\u003c/sup\u003e. However, at that time, there was no specific endpoint to rationally apply CNA in AF ablation. In the current study, based on the inception of the ECVS in 20152, we are not only reinforcing the initial observations from 20055\u0026nbsp;but also demonstrating that a negative VAFIT may serve as a valuable endpoint for predicting improved outcomes in AF ablation. Conversely, a positive VAFIT at the end of the procedure is strongly associated with a higher recurrence rate of AF, Figure 4, p=0.012. Considering that the denervation of the atrial walls is proportional to the number of AF-Nests ablated\u003csup\u003e15,16,17,18\u003c/sup\u003e, it can be inferred that after PVI, if the VAFIT remains positive, the CNA could be extended to achieve a negative VAFIT at the operator\u0026rsquo;s discretion, aiming to reduce long-term recurrences28,\u0026nbsp;Figure 4. Additionally, the multivariable analysis showed no significant other differences, probably due to the relatively healthy patients selected for the study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eElimination of Vagal Effect by CNA\u003cbr\u003e\u003c/strong\u003eA standard endpoint for CNA is the abolition of the vagal response in both the sinus and AV nodes guided by ECVS2. However, given anatomical variations and other intervening factors, a reduction of at least 90% in vagal effects (sinus pause and/or AV block duration) is often deemed adequate, as achieving total denervation may not be feasible in every case28. Notably, denervation of the sinus and AV nodes can occur while significant residual innervation of the atrial wall persists. Furthermore, significant vagal effect may persists after PVI, Figure 3-B,D. This suboptimal outcome may retain a considerable link to AF recurrence\u003csup\u003e19\u003c/sup\u003e,\u003csup\u003e20\u003c/sup\u003e, \u003csup\u003e21\u003c/sup\u003e,\u003csup\u003e22\u003c/sup\u003e. In this study, we observed that the cohort undergoing CNA with vagal effect elimination at all three domains \u0026ndash; sinus, AV node, and atrial wall \u0026ndash; exhibited a marked decrease in AF recurrence when compared to the group with residual vagal effects reflected by VAFIT-positive, Figure 4, p=0.012. \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEffect of Cardioneuroablation on Atrial Fibrillation Ablation\u003cbr\u003e\u003c/strong\u003eNumerous studies have indicated that PVI AF ablation leads to a certain degree of denervation and, it seems, that the greater the denervation, the better the outcome\u003csup\u003e23\u003c/sup\u003e,\u003csup\u003e24\u003c/sup\u003e,\u003csup\u003e25\u003c/sup\u003e,\u003csup\u003e26\u003c/sup\u003e. Typically, PVI reduces the degree of vagal response, yet a significant vagal effect induced by ECVS may persists post-PVI, Figure 3-B,D. The denervation by PVI is due to elimination of numerous AF-Nests in the PV antrum, which are indirectly ablated by various PVI techniques. However, CNA \u0026nbsp;controlled by ECVS is the election method to achieve complete vagal effect elimination17,\u003csup\u003e27\u003c/sup\u003e and the denervation of atrial walls is the most critical domain for this endpoint,\u0026nbsp;Figure 3-E,\u0026nbsp;Figure 5-B, and Table 1. The addition of CNA controlled with ECVS has a remarkable impact on PVI resulting in a substantial reduction in recurrence compared to PVI alone\u003csup\u003e28\u003c/sup\u003e.\u003c/p\u003e\n\u003cp\u003eCertainly, this technique could be further enriched with additional tests using isoproterenol and adenosine, particularly for detecting non-PV triggers, as it is likely that the VAFIT-positive group would be reduced with the identification and elimination these additional triggers.\u003csup\u003e29\u003c/sup\u003e\u003c/p\u003e\n\u003cp\u003eNevertheless, specific denervation endpoint of the atrial walls using CNA with ECVS has not been described. The VAFIT protocol can be a tool to measure the vagal effect on the atrial wall before and after any AF ablation technique. The electrophysiologist can utilize this parameter to pursue an additional endpoint and to have another predictive parameter for long-term outcomes. Naturally, replicating these findings in further studies is mandatory to solidify these conclusions.\u003cbr\u003e\u0026nbsp;A fundamental aspect in real-world practice is the training of operators to perform CNA. Typically, since they are already highly skilled in AF ablation, assimilating the CNA technique has been relatively straightforward. However, the key fundamental tool is the ECVS, as this resource allows operators to evaluate the progression of denervation, refining their expertise with each procedure and facilitating the comparison of results across various techniques and centers.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAssessment of Atrial Wall Denervation Following Cardioneuroablation\u003cbr\u003e\u003c/strong\u003eBeyond the sinus and AV node denervation, evaluating the extent of denervation in the atrial walls following CNA is challenging. The current study aims to propose a practical measurement for this parameter by using PAS under baseline and during ECVS2. ECVS typically causes a significant reduction in the EARP (Figure 6), and interestingly, an extra stimulus shorter than baseline EARP under ECVS elicits AF induction before CNA, Figure 2-B, Figure 3-D, and Figure 5-A. This observation forms the basis of the VAFIT proposed in this study, a tool for measuring the innervation on the atrial walls. Before ablation, VAFIT typically induces AF, Figure 2-B, and Figure 5-A. However, after CNA with significant denervation, VAFIT usually becomes negative, no longer triggering AF, which indicates the elimination of the vagal effect in the atrial wall. Despite some degree of denervation, after PVI only, VAFIT may continue positive when significant vagal innervation persists, Figure 3-D. However, Figure 4 shows that a VAFIT-negative status would be better as it significantly correlates with AF recurrence reduction.\u003c/p\u003e\n\u003cp\u003eIn this study, all cases underwent denervation. However, those achieving a VAFIT-negative post-ablation had a 4.56-fold reduction in recurrence, indicating that the degree of vagal denervation, specifically in the atrial walls, is highly correlated with the long-term success of AF ablation, Figure 4.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eRemarkable Atrial Refractoriness Modification by Vagal Effect and by CNA\u003cbr\u003e\u003c/strong\u003eAs a collateral observation, Figure 6 summarizes atrial refractoriness with ECVS and CNA. Before ablation, only a slight refractory dispersion is observed between the atria (Figure 6-C, 1A-1B). However, during ECVS, there is a profound reduction in EARP (Figure 6, 2A-2B), resulting in a remarkable refractory dispersion (Figure 6-D, 2A-2B), which triggers the AF induction by a single extra stimulus with a coupling interval shorter than the baseline EARP featuring the VAFIT-positive status. Following CNA, a drastic change toward normalization is observed (Figure 6-E, 3A-3B). Thus, CNA not only tends to increase the EARP of the atrial walls (Figure 6-3A-3B) but, more critically, it may eliminate the vagally induced refractory dispersion (Figure 6-D versus E), evidenced by the absence of a refractoriness vagal response. This leads to a marked enhancement of atrial electrical stability, demonstrated by the VAFIT-positive status shifting to negative.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eLeft Atrium Refractoriness Behavior\u003c/strong\u003e\u003cbr\u003eAs AF ablation is more extensive in the LA, it often results in more pronounced LA vagal denervation, which can manifest as an EARP increase post-PVI+CNA compared to the basal EARP, likely attributable to a decrease in LA basal vagal tone (Figure 6, 1B versus 3B). Conversely, the RA undergoes less extensive ablation, potentially leading to a modest increase in interatrial refractoriness dispersion, Figure 6-E. However, this change was not statistically significant (Figure 6, C vs E, p=0.051) and could be mitigated by further AF-Nests ablation in the RA if needed. Still considering Figure 6, it is essential to note that the refractory dispersion in E is different from C, as C is dynamic and transitions to D under vagal influence. In contrast, no such vagal effect persists post-CNA, rendering the E dispersion static and invariant, thereby considerably safer than the pre-CNA condition C.\u003c/p\u003e\n\u003cp\u003eThese data suggest that vagal denervation is one cornerstone of AF ablation, and that implementing vagal denervation via CNA during PVI may significantly benefit the patient28. Consequently, we consider PVI and CNA complementary methods in AF ablation. The latter can be easily achieved using the classic CNA technique controlled by ECVS, which involves anatomical mapping and ablation of AF-Nests if necessary. Furthermore, the VAFIT protocol may be a useful reproducible electrophysiological endpoint for reducing recurrences.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eVagal Induced Refractory Dispersion\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAcetylcholine causes an intense potassium efflux, immediate hyperpolarization, and reduction in the action potential duration and refractoriness. Unlike skeletal muscle, which has a motor endplate that prevents acetylcholine dispersion in a close model, the atrial myocardium has a non-specialized open neuro-myocardial junction featured by AF-Nests, Figure 7. This allows for heterogeneous acetylcholine diffusion, Figure 7-A and C. As a result, neighboring cells experience abrupt and vast differences in acetylcholine concentration, causing a significant and sudden refractory dispersion, Figure 7-B and C, that easily triggers AF. This supports the VAFIT concept and accounts for the significant reduction in post-PVI recurrence when combined with CNA, which includes wide denervation of the atrial wall.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eLimitations\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWhile providing novel insights into the efficacy of VAFIT-negative status as an endpoint for AF ablation, this study carries certain limitations that warrant consideration. Despite indicating a substantial reduction in AF recurrence, a longer follow-up should be considered. Highly selected patients with a low degree of heart disease may not accurately represent real-world populations. \u0026nbsp; Single-center study could introduce a selection bias and limit the generalizability of the findings. Although ECVS may be easily performed with neurological stimulators, the ECVS may limit the availability in some centers. The use of extra stimuli to induce AF may not replicate the natural onset of AF in some patients, which could potentially skew the results. Technical aspects of this technique depend on a minimal learning curve to get reliable and reproducible results. Another limitation is that VAFIT was performed only at baseline and after completion of the whole procedure (PVI+CNA). Therefore, separate effects of PVI and CNA were not explicitly evaluated despite VAFIT-positive was observed in several patients after PVI. Further research with a larger, multi-center cohort and a longer follow-up are necessary to validate the conclusions and ensure the reproducibility of the VAFIT-negative endpoint in broader clinical practice.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eBy achieving a negative VAFIT (Vagal AF Induction Test) status, cardioneuroablation plus PVI successfully reduced AF recurrence by 4.5-fold. Moreover, this approach effectively eliminated the massive atrial refractory dispersion sharply induced by vagal effects. Thus, achieving a VAFIT-negative status seems to be an useful and rational endpoint in AF ablation. The specific validation of atrial wall denervation through extra-cardiac vagal stimulation and programmed atrial stimulation was crucial to these outcomes.\u003c/p\u003e"},{"header":"Abbreviation","content":"\u003cp\u003eAF\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;Atrial Fibrillation\u003c/p\u003e\n\u003cp\u003eAF-Nest\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u0026nbsp;Atrial Fibrillation Nests (poorly connected myocardium spots)\u003c/p\u003e\n\u003cp\u003eAPS\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u0026nbsp;Atrial Programmed Stimulation\u003c/p\u003e\n\u003cp\u003eAT \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u0026nbsp;Atrial Tachycardia\u003c/p\u003e\n\u003cp\u003eAV\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;Atrioventricular\u003c/p\u003e\n\u003cp\u003eAVB\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u0026nbsp;Atrioventricular Block\u003c/p\u003e\n\u003cp\u003ebpm\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u0026nbsp;beats per minute\u003c/p\u003e\n\u003cp\u003eCNA\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u0026nbsp;Cardioneuroablation\u003c/p\u003e\n\u003cp\u003eEARP\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u0026nbsp;Effective Atrial Refractory Period\u003c/p\u003e\n\u003cp\u003eECVS\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u0026nbsp;Extra-Cardiac Vagal Stimulation\u003c/p\u003e\n\u003cp\u003eEF\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;Ejection Fraction\u003c/p\u003e\n\u003cp\u003eGP\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;Ganglionated Plexus\u003c/p\u003e\n\u003cp\u003eHR\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;Heart Rate\u003c/p\u003e\n\u003cp\u003eIQR\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u0026nbsp;Interquartile range\u003c/p\u003e\n\u003cp\u003eLA\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;Left atrium\u003c/p\u003e\n\u003cp\u003ePAS\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u0026nbsp;Programmed Atrial Stimulation\u003c/p\u003e\n\u003cp\u003ePs\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u0026nbsp;Persistent\u003c/p\u003e\n\u003cp\u003ePx\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u0026nbsp;Paroxysmal\u003c/p\u003e\n\u003cp\u003ePVI\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u0026nbsp;Pulmonary Vein Isolation\u003c/p\u003e\n\u003cp\u003ePV\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;Pulmonary Vein \u0026nbsp;\u003c/p\u003e\n\u003cp\u003eSD\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;Standard Deviation\u003c/p\u003e\n\u003cp\u003eVAFIT \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; Vagal Atrial Fibrillation Induction Test\u003c/p\u003e"},{"header":" References","content":"\u003col\u003e\n\u003cli\u003eSantangeli P, Zado ES, Garcia FC, Riley MP, Lin D, Frankel DS, Supple GE, Schaller RD, Dixit S, Callans DJ, Marchlinski FE. 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PMID: 21454332.\u003c/li\u003e\n\u003cli\u003eChang HY, Lo LW, Lin YJ, Lee SH, Chiou CW, Chen SA. Relationship between intrinsic cardiac autonomic ganglionated plexi and the atrial fibrillation nest. Circ J. 2014;78(4):922-8. doi: 10.1253/circj.cj-13-1053. Epub 2014 Feb 24. PMID: 24562675.\u003c/li\u003e\n\u003cli\u003eZhao Y, Jiang Z, Tsai W-C, Yuan Y, Chinda K, Choi E-K, et al. Ganglionated plexi and ligament of Marshall ablation reduces atrial vulnerability and causes stellate ganglion remodeling in ambulatory dogs n.d. doi:10.1016/j.hrthm.2016.07.014.\u003c/li\u003e\n\u003cli\u003ePachon JC, Pachon EI, Cunha Pachon MZ, Lobo TJ, Pachon JC, Santillana TG. Catheter ablation of severe neurally meditated reflex (neurocardiogenic or vasovagal) syncope: cardioneuroablation long-term results. Europace. 2011 Sep;13(9):1231-42. doi: 10.1093/europace/eur163. Epub 2011 Jun 28. 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PMID: 38609733.\u003c/li\u003e\n\u003cli\u003eParlavecchio A, Vetta G, Coluccia G, Pistelli L, Caminiti R, Ajello M, Magnocavallo M, Dattilo G, Foti R, Carerj S, Crea P, Accogli M, Chierchia GB, de Asmundis C, Della Rocca DG, Palmisano P. Catheter ablation in patients with paroxysmal atrial fibrillation and absence of structural heart disease: A meta-analysis of randomized trials. Int J Cardiol Heart Vasc. 2023 Nov 5;49:101292. doi: 10.1016/j.ijcha.2023.101292.\u003c/li\u003e\n\u003cli\u003eMorillo CA, Verma A, Connolly SJ, Kuck KH, Nair GM, Champagne J, et al. Radiofrequency ablation vs antiarrhythmic drugs as first-line treatment of paroxysmal atrial fibrillation (RAAFT-2) a randomized trial. JAMA - Journal of the American Medical Association 2014;311:692\u0026ndash;699. doi:10.1001/jama.2014.467.\u003c/li\u003e\n\u003cli\u003ePachon-M JC and Pachon M EI. US20110098699A1 - Apparatus and Methods for Arrhythmia Treatment Based on Spectral Mapping During Sinus Rhythm - Google Patents. 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PACE - Pacing and Clinical Electrophysiology 2010;33:1497\u0026ndash;1503. doi:10.1111/J.1540-8159.2010.02834.X.\u003c/li\u003e\n\u003cli\u003ePachon-M EI, Pachon-Mateos JC, Higuti C, Santillana-P TG, Lobo T, Pachon C, et al. Relation of Fractionated Atrial Potentials with the Vagal Innervation Evaluated by Extracardiac Vagal Stimulation during Cardioneuroablation. Circulation: Arrhythmia and Electrophysiology 2020:302\u0026ndash;313. doi:10.1161/CIRCEP.119.007900.\u003c/li\u003e\n\u003cli\u003eArruda M, Natale A. Ablation of permanent AF - Adjunctive strategies to pulmonary veins isolation: Targeting AF NEST in sinus rhythm and CFAE in AF. Journal of Interventional Cardiac Electrophysiology 2008;23:51\u0026ndash;57. doi:10.1007/S10840-008-9252-Z.\u003c/li\u003e\n\u003cli\u003eKang KW, Kim TH, Park J, Uhm JS, Joung B, Hwang C, Lee MH, Pak HN. Long-term changes in heart rate variability after radiofrequency catheter ablation for atrial fibrillation: 1-year follow-up study with irrigation tip catheter. J Cardiovasc Electrophysiol. 2014 Jul;25(7):693-700. doi: 10.1111/jce.12398. Epub 2014 Mar 28. PMID: 24575794.\u003c/li\u003e\n\u003cli\u003eOlgin JE, Sih HJ, Hanish S, Jayachandran JV, Wu J, Zheng QH, Winkle W, Mulholland GK, Zipes DP, Hutchins G. Heterogeneous atrial denervation creates substrate for sustained atrial fibrillation. Circulation. 1998 Dec 8;98(23):2608-14. doi: 10.1161/01.cir.98.23.2608. PMID: 9843470.\u003c/li\u003e\n\u003cli\u003eDrexler M, Blum T, Heinroth KM, Hartkopf T, Plehn A, Schirdewahn P, Sedding DG. Heart rate variability as a predictor of successful catheter-guided pulmonary vein isolation for atrial fibrillation. Herz. 2024 Mar;49(2):147-154. doi: 10.1007/s00059-023-05201-6. Epub 2023 Aug 17. PMID: 37589750; PMCID: PMC10917838.\u003c/li\u003e\n\u003cli\u003eCălburean PA, Osorio TG, Sorgente A, Almorad A, Pannone L, Monaco C, Miraglia V, Al Housari M, Mojica J, Bala G, Bisignani A, Lipartiti F, Strazdas A, Ramak R, Overeinder I, La Meir M, Str\u0026ouml;ker E, Brugada P, Boveda S, Paparella G, Iacopino S, Sieira J, Chierchia GB, de Asmundis C. High vagal tone predicts pulmonary vein reconnection after cryoballoon ablation for paroxysmal atrial fibrillation. Pacing Clin Electrophysiol. 2021 Dec;44(12):2075-2083. doi: 10.1111/pace.14408. Epub 2021 Nov 26. PMID: 34773413.\u003c/li\u003e\n\u003cli\u003eKatritsis DG, Pokushalov E, Romanov A, Giazitzoglou E, Siontis GCM, Po SS, et al. Autonomic denervation added to pulmonary vein isolation for paroxysmal atrial fibrillation: a randomized clinical trial. J Am Coll Cardiol 2013;62:2318\u0026ndash;2325.\u003c/li\u003e\n\u003cli\u003eLiao TE, Li CH, Lin YJ, Chang SL, Hu YF, Chung FP, Chao TF, Liao JN, Yang HW, Lo MT, Chen SA, Lo LW. Fractal complexity alternations in paroxysmal atrial fibrillation patients with and without recurrence after pulmonary vein isolation. Ann Noninvasive Electrocardiol. 2023 Sep;28(5):e13074. doi: 10.1111/anec.13074. Epub 2023 Jul 19. PMID: 37469220; PMCID: PMC10475888.\u003c/li\u003e\n\u003cli\u003eZhang E, Liang S, Sun T, Xu J, Lu F, Wu D, Zhang J, He L, Zhang F, Fan S, Ma W. Prognostic value of heart rate variability in atrial fibrillation recurrence following catheter ablation: A systematic review and meta-analysis. Front Cardiovasc Med. 2023 Feb 2;9:1048398. doi: 10.3389/fcvm.2022.1048398. PMID: 36818913; PMCID: PMC9932203.\u003c/li\u003e\n\u003cli\u003eKampaktsis PN, Oikonomou EK, Y. Choi D, Cheung JW. Efficacy of ganglionated plexi ablation in addition to pulmonary vein isolation for paroxysmal versus persistent atrial fibrillation: a meta-analysis of randomized controlled clinical trials. Journal of Interventional Cardiac Electrophysiology 2017;50:253\u0026ndash;260. doi:10.1007/s10840-017-0285-z.\u003c/li\u003e\n\u003cli\u003eSarabanda AV, Melo SL, Rivarola E, Hachul D, Scanavacca M. Anatomically guided atrial ganglionated plexus ablation evaluated by extracardiac vagal stimulation for vagally mediated atrioventricular block. HeartRhythm Case Rep. 2021 Feb 10;7(5):301-305. doi: 10.1016/j.hrcr.2021.02.002. PMID: 34026520; PMCID: PMC8134772.\u003c/li\u003e\n\u003cli\u003ePachon-M EI, Clark J, Lobo TJ, Pachon CT, Higuti C, Pachon MZ, Ortencio F, Amarante RC, Osorio TG. Impact of Cardioneuroablation with Vagal Denervation Confirmed by Vagus Nerve Stimulation on Pulmonary Vein Isolation for Atrial Fibrillation Catheter Ablation. Journal of Atrial Fibrillation \u0026amp; Electrophysiology. 2023 Nov 1;16(8).\u003c/li\u003e\n\u003cli\u003eElayi CS, Di Biase L, Bai R, Burkhardt JD, Mohanty P, Santangeli P, Sanchez J, Hongo R, Gallinghouse GJ, Horton R, Bailey S. Administration of isoproterenol and adenosine to guide supplemental ablation after pulmonary vein antrum isolation. Journal of cardiovascular electrophysiology. 2013 Nov;24(11):1199-206.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Atrial Fibrillation, ablation, cardioneuroablation, pulmonary vein isolation, denervation, autonomic nervous system, syncope, refractory dispersion","lastPublishedDoi":"10.21203/rs.3.rs-5643881/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-5643881/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eIntroduction\u003c/p\u003e \u003cp\u003eCurrently, 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.\u003c/p\u003e \u003cp\u003eThis 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.\u003c/p\u003e \u003cp\u003eMethods\u003c/p\u003e \u003cp\u003eProspective study of 142 patients, 57.5[48.9\u0026ndash;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\u0026thinsp;+\u0026thinsp;CNA, with a single atrial extra stimulus during ECVS (5s/50Hz/1V/kg up to 70V/Pulse Width\u0026thinsp;=\u0026thinsp;50 \u0026micro;s). Patients were followed for a median of 15.0[7.0\u0026ndash;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.\u003c/p\u003e \u003cp\u003eResults\u003c/p\u003e \u003cp\u003ePre-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\u0026thinsp;=\u0026thinsp;0.012). VAFIT-positivity was associated with AF recurrence (HR: 4.56(1.37\u0026ndash;15.23,p\u0026thinsp;=\u0026thinsp;0.014).\u003c/p\u003e \u003cp\u003eConclusion\u003c/p\u003e \u003cp\u003eA VAFIT-positive status following PVI\u0026thinsp;+\u0026thinsp;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.\u003c/p\u003e","manuscriptTitle":"Vagal AF Induction Test (VAFIT): A New Endpoint for Optimizing Atrial Fibrillation Ablation through Cardioneuroablation","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-12-23 16:27:21","doi":"10.21203/rs.3.rs-5643881/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"57a380e2-5cd2-4b41-aa6c-ab7d0df95162","owner":[],"postedDate":"December 23rd, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":41602619,"name":"Cardiac \u0026 Cardiovascular Systems"}],"tags":[],"updatedAt":"2024-12-23T16:27:21+00:00","versionOfRecord":[],"versionCreatedAt":"2024-12-23 16:27:21","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-5643881","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-5643881","identity":"rs-5643881","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}