Background - Several disorders present reflex or persistent increase in vagal tone that may cause refractory symptoms even in a normal heart patient. Cardioneuroablation (CNA), the vagal denervation by RF ablation of the neuromyocardial interface, was developed to treat these conditions without pacemaker implantation. A theoretical limitation could be the reinnervation, that naturally grows in the first year, that could recover the vagal hyperactivity. This study aims to verify the vagal denervation degree in the chronic phase after CNA. Additionally, it intends to investigate the arrhythmias behavior after CNA. Methods - prospective longitudinal study with intra-patient comparison of 83 very symptomatic cases without significant cardiopathy, submitted to CNA, 49(59%) male, 47.3±17 years-old, having vagal paroxysmal atrial fibrillation 58(70%) or neurocardiogenic syncope 25(30%), NYHA Class < II and absence of significant comorbidities. CNA was performed in both atria by interatrial septum puncture, with irrigated conventional catheter and electroanatomic reconstruction. Ablation targeted the neuromiocardial interface by fragmentation mapping (AF-Nests) using the Velocity Fractionation software, conventional recording and anatomical localization of the ganglionated plexi. There were compared the time and frequency domain of the heart rate variability (HRV) and arrhythmias in 24h Holter pre-, 1-year-post- and 2-year-post-CNA. Clinical outpatient follow-up and serial Holter showed 80% asymptomatic cases at 40 months. Results - Time and frequency domain HRV demonstrated significant decrease in all autonomic parameters, showing an important parasympathetic and sympathetic activity reduction at 2 years-post-CNA (p<0.001). There was no difference in HRV between the 1-year- and 2-post-CNA (p>0.05) suggesting that the reinnervation has halted. There was also an important reduction in all brady- and tachyarrhythmias pre- vs. post-CNA, (p <0.01). Conclusions - There is an important and significant vagal and sympathetic denervation after 2 years of CNA with a significant reduction in brady and tachyarrhythmia in the whole group. There were no complications.

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BackgroundDespite great progress, the long-term outcomes of catheter ablation for long standing atrial fibrillation (LSAF) remain suboptimal [1], [2] . Pulmonary vein isolation (PVI) [3], [4] is recognized as the cornerstone for paroxysmal atrial fibrillation (AF) ablation [5], [6], [7] but insufficient as a stand-alone ablation approach for LSAF [8], [9] .The adjunct of linear ablation lesion sets [10], [11], [12] ; ablation of complex fractionated atrial electrograms (CFAE) [13], [14] ; extensive ablation including the left atrial (LA) posterior wall [15] , superior vena cava (SVC) [16] , coronary sinus and LA appendage or even vagal denervation [17], [18] may improve outcomes slightly but compromises procedural complexity and safety [19], [20], [21] . We have found that the AF Nests (AFN) ablation had a favorable impact on the long-term outcome after a single procedure [22], [23] . It decreased overall recurrences as compared to our conventional PV antral isolation plus CFAE ablation [24] . Interestingly, following PVI and AFN ablation,most recurrences are caused by an organized, typically fast atrial tachycardia. This residual tachycardia often appears as a transitional rhythm during AF ablation upon its organization or termination,[ Figure 1] By using spectral analysis with Fast Fourier Transform (FFT) we have found that this tachycardia is present during AF, before ablation, [25] which we have named "Background Tachycardia" (BT) [22], [26], [27] . Rapid atrial pacing following PVI and AFN ablation can also commonly induce one or more of these organized atrial tachycardias. By studying this tachycardia with spectral mapping we have found that it commonly arises from an AFN exhibiting a specific case of focal microreentry, (fractal microreentry [25] ), characterized by entry block, which ensures its maintenance during AF without overdrive reversion by the AF itself. In this study, we evaluated the long-term outcome of BT ablation as an adjunct to PVI plus substrate modification by AFN ablation in patients with LSAF. In addition, we assessed the feasibility of identifying the BT by digital processing and spectral analysis of the AF on the surface electrocardiogram (ECG) prior to the ablation procedure. Patients and methods Study PopulationIn this prospective study were enrolled 114 consecutive patients with www.jafib.com Aug-Sep 2017| Volume 10| Issue 2 AbstractBackground: Catheter ablation of long-standing persistent AF (LSAF) remains challenging. Since AF-Nest (AFN) description, we have observed that a stable, protected, fast source firing, namely "Background Tachycardia"(BT), could be hidden beneath the chaotic AF. Following pulmonary vein isolation (PVI)+AFN ablation one or more BT may arise or be induced in 30-40% of patients, which could be the culprit forAF maintenance and ablation recurrences.Methods and Results: We studied 114 patients, from 322 sequential LSAF regular ablations, having spontaneous or induced residual BT after EGM-guided PVI+AFN ablation of LSAF; 55.6±11y/o, 97males (85.1%), EF=65.5±...