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Background: Cardioneuroablation (CNA) is a novel therapeutic approach for functional bradyarrhythmias, specifically neurocardiogenic syncope or atrial fibrillation, achieved through endocardial radiofrequency catheter ablation of vagal innervation, obviating the need for pacemaker implantation. Originating in the nineties, the first series of CNA procedures was published in 2005. Extra‐cardiac vagal stimulation (ECVS) is employed as a direct method for stepwise denervation control during CNA. Objective: This study aimed to compare the long‐term follow‐up outcomes of patients with severe cardioinhibitory syncope undergoing CNA with and without denervation confirmation via ECVS. Method: A cohort of 48 patients, predominantly female (56.3%), suffering from recurrent syncope (5.1 ± 2.5 episodes annually) that remained unresponsive to clinical and pharmacological interventions, underwent CNA, divided into two groups: ECVS and NoECVS, consisting of 34 and 14 cases, respectively. ECVS procedures were conducted with and without atrial pacing. Results: Demographic characteristics, left atrial size, and ejection fraction displayed no statistically significant differences between the groups. Follow‐up duration was comparable, with 29.1 ± 15 months for the ECVS group and 31.9 ± 20 months for the NoECVS group (p =.24). Notably, syncope recurrence was significantly lower in the ECVS group (two cases vs. four cases, Log Rank p =.04). Moreover, the Hazard ratio revealed a fivefold higher risk of syncope recurrence in the NoECVS group. Conclusion: This study demonstrates that concluding CNA with denervation confirmation via ECVS yields a higher success rate and a substantially reduced risk of syncope recurrence compared to procedures without ECVS confirmation. [ABSTRACT FROM AUTHOR]

Idiopathic Ventricular Premature Contraction (VPC) is currently more routinely referred for electrophysiology evaluation. Usually it carries a good prognosis but, when symptomatic or suspected to produce ventricular dysfunction, will require treatment. Nowadays, RF ablation has great advantages over antiarrhythmic drugs. Classically the outflow tract (right or left), with the typical inferior axis with left (eventually right) bundle brunch block like ECG morphology, is considered the most frequent site of origin for idiopathic VPC, but with the widespread of EP procedures and advancement of technology making possible to map and ablate difficult locations, it is possible to see a growing and changing population referred for idiopathic VPC ablation, displaying that, almost any region of the heart may be source of this kind of arrhythmia that can be successfully treated. A well-planned procedure, with the presumed region of origin settled and employing the current technology and knowledge (tips), will have a high chance of cure. [ABSTRACT FROM AUTHOR]

Background By studying the spectrum of atrial potentials by fast Fourier transform (FFT) we have found two types of atrial muscle: the compact (CM) and the fibrillar (FM) myocardium. The former presents normal in-phase conduction inferring a great number of cellular connections, long-lasting refractoriness and leftward FFT-shift. The latter shows anisotropic out-of-phase conduction, fewer cellular connections, short refractoriness and a segmented right-FFT-shift. The compact is the normal predominant muscle and the fibrillar is different and may be neural input, vein insertion, interatrial (1A) septum, left atrial (LA) roof, etc. or pathological tissue, being so by loss of cellular connections this is a possible mechanism for conversion of compact into fibrillar-like myocardium. During atrial fibrillation (AF), clusters of FM (AF nests) present higher frequencies than any surrounding tissue. Purpose The purpose was to describe a new method for paroxysmal AF RF-ablation targeting AF nests. Method Forty patients, six control and 34 having idiopathic drug-refractory paroxysmal or persistent AF were studied and treated. Two catheters were placed in the LA by transseptal approach. RF (30–40 J/60–70 °C) was applied to all sites outside the pulmonary veins (PV) presenting right-FFT-shift (AF nests). Results Numerous AF nests were found in 34/34 AF patients and only in 1/6 controls (only in this case it was possible to induce AF despite an absence of AF history). The main FM sites were: LA roof, LA septum, close to the insertion of the superior PV, near the insertion of the inferior PV, LA posterior wall, RA near the superior vena cava insertion, RA lateral and anterior wall and the right IA septum. Ablation of all AF nests near PV insertions resulted in 35 PV isolations. After 9.9 ± 5 months only two AF patients presented relapse of a different AF form (coarse AF) which was very well controlled with medication previously ineffective. The AF was more frequent as the ratio FM/CM increased. Conclusions The RF-ablation of AF nests decreasing the fibrillar/compact myocardium ratio eliminated 94% of the paroxysmal AF in patients in the FU of 9.9 ± 5 months. The AF nests may be easily identified by spectral analysis and seem to be the real AF substrate. Paroxysmal AF may be cured or controlled by applying RF in several places outside the PV and, thereby, avoiding PV stenosis. [ABSTRACT FROM PUBLISHER]

Background: Despite good results, atrial fibrillation (AF) ablation shows a relatively high recurrence rate. Therefore, we sought to verify whether endocardial denervation by cardioneuroablation (CNA) can change the AF recurrence post-pulmonary vein isolation (PVI). Objective: To compare the long-term AF recurrence post-PVI versus PVI, plus vagal denervation (PVI+CNA) by CNA with vagal denervation confirmation by extracardiac vagal stimulation (ECVS). Methods: Case-control study of 127 patients, 104 (81.9%) males, 53.7 ± 12 years-old, with paroxysmal 71 (55.9%) or persistent 56 (44.1%) symptomatic AF, refractory to medications without cardiopathy, LA = 39.8 ± 6.8, EF = 0.66 ± 0.55. Two equivalent groups were established: PVI alone (55 cases) and PVI+CNA (72 cases). The ECVS was performed by intravenous catheter, near the jugular foramen with 50Hz/50microsec/1V/Kg/up to 70V. Endocardial CNA was biatrial over the four main ganglionated plexus and in the AF-Nests regions tagged by fractionation software. The endpoint of CNA was the elimination of the vagal effect induced by ECVS. Results: PVI was achieved in all cases. ECVS effectively induced a vagal reaction in all PVI+CNA patients, and it was possible to eliminate the vagal effect in 88.9% of cases. In 11.1% of cases, there was a slight residual vagal response. Patients were followed up to 45 months (mean FU = 21.4 ± 14.2 and 20.4 ± 14.3 months). Recurrences were 17 in the PVI group, and four in the PVI+CNA group: Log-Rank p < 0.00, HR: 5.38 (1.78-16.29, p = 0.003). No major complications occurred. Conclusion: Addition of vagal denervation to PVI, with validation of the vagal denervation by ECVS, significantly increased the success rate of the PVI with a marked reduction in AF relapses without increasing complications. [ABSTRACT FROM AUTHOR]

Background: Carotid sinus syndrome (CSS) is a condition caused by sudden autonomic nervous system imbalance with vagal overactivity. It may lead to sinus bradycardia, sinus arrest, and AV block with severe symptoms and syncope, which may be treated with a pacemaker (PM). Cardioneuroablation (CNA) is an atrial endocardial catheter radiofrequency (RF) ablation aiming vagal denervation that could be used to remove the cardioinhibitory response in the CSS as suggested in the original study. Objective: To study the outcome of CNA controlled by extracardiac vagal stimulation (ECVS) in patients with CSS without significant cardiopathy. Methods: Prospective, controlled study of eight patients with symptomatic CSS, positive carotid sinus massage (CSM), and normal atropine response. Bi-atrial RF-ablation of the neuro endo-myocardial interface was guided by filtered endocardial electrograms, fractionation, and 3D anatomical mapping, identifying AF-Nests (AFN) related to the four main ganglionic plexuses (GP) with bi-atrial RF ablation (irrigated catheter 30W/42°C/20-60s). ECVS (5s) at the left jugular foramen and CSM was performed before, during, and at the end of the ablation to guide the level of denervation, defining the higher CNA effect and end of the procedure, analyzing pauses and AVB, induced by ECVS and CSM. Results: The mean age of patients was 58.6 (± 11.8). Pre-CNA, CSM, and ECVS responses were asystole and transient AVB in all patients. Post-CNA, ECVS, and Atropine responses were completely abolished in seven out of eight patients. In a 31 ± 16.1 months follow up, one case with incomplete CNA experienced syncope recurrence due to AVB and was submitted to a new CNA for AVB becoming asymptomatic. Another case had a positive CSM six months after CNA and had a pacemaker (PM) implanted even though asymptomatic, as per his physician's discretion. There was immediate sustained HR (58.9 ± 12,7/81,8 ± 4.9 bpm) and Wenckebach's point increase (133.5 ± 39.2 / 164.7 ± 10.8ppm), p: < 0,01. Conclusion: Complete bi-atrial CNA vagal denervation, based on AFN/GP ablation guided by vagal effect abolishment confirmed by ECVS and CSM responses, was effective in eliminating syncope recurrence in all patients with CSS. [ABSTRACT FROM AUTHOR]

Idiopathic Ventricular Premature Contraction (VPC) is currently more routinely referred for electrophysiology evaluation. Usually it carries a good prognosis but, when symptomatic or suspected to produce ventricular dysfunction, will require treatment. Nowadays, RF ablation has great advantages over antiarrhythmic drugs. Classically the outflow tract (right or left), with the typical inferior axis with left (eventually right) bundle brunch block like ECG morphology, is considered the most frequent site of origin for idiopathic VPC, but with the widespread of EP procedures and advancement of technology making possible to map and ablate difficult locations, it is possible to see a growing and changing population referred for idiopathic VPC ablation, displaying that, almost any region of the heart may be source of this kind of arrhythmia that can be successfully treated. A well-planned procedure, with the presumed region of origin settled and employing the current technology and knowledge (tips), will have a high chance of cure.

Background: Two types of myocardia can be observed through the endocardial spectral mapping (SM) in sinus rhythm: the compact type with a smooth spectrum and the fibrillar type with a segmented spectrum (atrial fibrillation nests). During the atrial fibrillation (AF), the compact type has an organized activation and low frequency (passive), whereas the fibrillar type has a rather disorganized activation and high frequency (active/resonant), with both being activated by high-frequency sustained tachycardia--the background tachycardia (BT)., Objective: To describe the treatment of AF by the ablation of the AF nests and BT., Methods: 1) Catheter ablation of the AF nests with RF [4/8 mm-60 masculine/30-40 J/30s] guided by SM in sinus rhythm, outside the pulmonary vein; 2) atrial stimulation -300 ppm; 3) Additional ablation of the AF nests if AF is induced; 4) Focal ablation if BT and/or Flutter is induced; 5) Clinical follow-up+ ECG+ Holter., Results: A total of 50+/-18 AF nests/patient were treated. After 11.3+/-8 m, 81 patients (88%) did not present AF (28.3% with antiarrhythmic drugs). After the ablation of the AF nests, AF was not reinduced in 61 patients (71%) and BT was induced and treated in 24 patients (26%). There were two episodes of pericardial bleeding (1 treated clinically and 1 surgically), caused by sheaths that are no longer used, Conclusion: The SM in sinus rhythm can be used in the ablation of AF nests. During the AF, the AF nests present a reactive-resonant pattern and the compact myocardium is passive, stimulated by the high frequency of the BT. After the ablation of the AF nests and the BT, it was not possible to reinduce the sustained AF. The Ablation of AF nests outside the pulmonary veins showed to be safe and highly effective in the cure and/or clinical control of the AF.

Cardiac neuroablation is a new technique for management of patients with dominantly adverse parasympathetic autonomic influence. The technique is based on radiofrequency (RF) ablation of autonomic connections in the three main ganglia around the heart. Their connections are identified by Fast-Fourier Transforms (FFTs) of endocardial signals: sites of autonomic nervous connections show fractionated signals with FFTs shifted to the right. In contrast, normal myocardium without these connections does not show these features. RF-ablation is thought to inflict permanent damage on the parasympathetic autonomic influence because its cells are adjacent to the heart whereas sympathetic cells are remote. Twenty-one patients with a mean age of 48 years, neurally mediated reflex syncope in six, functional high grade atrioventricular block in seven and sinus node dysfunction in 13 (there is overlap between the second and third groups) were treated. Follow-up for a mean of 9.2 months demonstrated success in all cases with relief of symptoms. No complications occurred.

Background: By studying the spectrum of atrial potentials by fast Fourier transform (FFT) we have found two types of atrial muscle: the compact (CM) and the fibrillar (FM) myocardium. The former presents normal in-phase conduction inferring a great number of cellular connections, long-lasting refractoriness and leftward FFT-shift. The latter shows anisotropic out-of-phase conduction, fewer cellular connections, short refractoriness and a segmented right-FFT-shift. The compact is the normal predominant muscle and the fibrillar is different and may be neural input, vein insertion, interatrial (1A) septum, left atrial (LA) roof, etc. or pathological tissue, being so by loss of cellular connections this is a possible mechanism for conversion of compact into fibrillar-like myocardium. During atrial fibrillation (AF), clusters of FM (AF nests) present higher frequencies than any surrounding tissue., Purpose: The purpose was to describe a new method for paroxysmal AF RF-ablation targeting AF nests., Method: Forty patients, six control and 34 having idiopathic drug-refractory paroxysmal or persistent AF were studied and treated. Two catheters were placed in the LA by transseptal approach. RF (30-40 J/60-70 degrees C) was applied to all sites outside the pulmonary veins (PV) presenting right-FFT-shift (AF nests)., Results: Numerous AF nests were found in 34/34 AF patients and only in 1/6 controls (only in this case it was possible to induce AF despite an absence of AF history). The main FM sites were: LA roof, LA septum, close to the insertion of the superior PV, near the insertion of the inferior PV, LA posterior wall, RA near the superior vena cava insertion, RA lateral and anterior wall and the right IA septum. Ablation of all AF nests near PV insertions resulted in 35 PV isolations. After 9.9 +/- 5 months only two AF patients presented relapse of a different AF form (coarse AF) which was very well controlled with medication previously ineffective. The AF was more frequent as the ratio FM/CM increased., Conclusions: The RF-ablation of AF nests decreasing the fibrillar/compact myocardium ratio eliminated 94% of the paroxysmal AF in patients in the FU of 9.9 +/- 5 months. The AF nests may be easily identified by spectral analysis and seem to be the real AF substrate. Paroxysmal AF may be cured or controlled by applying RF in several places outside the PV and, thereby, avoiding PV stenosis.