Distance-dependent neuromodulation effect during thermal ablation for atrial fibrillation.

INTRODUCTION: Thermal atrial fibrillation (AF) ablation exerts an additive treatment effect on the cardiac autonomic nervous system (CANS). This effect is mainly reported during ablation of the right superior pulmonary vein (RSPV), modulating the right anterior ganglionated plexus (RAGP), which contains parasympathetic innervation to the sinoatrial node in the epicardial fat pad between RSPV and superior vena cava (SVC). However, a variable response to neuromodulation after ablation is observed, with little to no effect in some patients. Our objective was to assess clinical and anatomic predictors of thermal ablation-induced CANS changes, as assessed via variations in heart rate (HR) postablation. METHODS: Consecutive paroxysmal AF patients undergoing first-time PV isolation by the cryoballoon (CB) or radiofrequency balloon (RFB) within a 12-month time frame and with preprocedural cardiac computed tomography (CT), were evaluated. Preablation and 24-h postablation electrocardiograms in sinus rhythm were collected and analyzed to assess HR. Anatomic evaluation by CT included the measurement of the shortest distance between the SVC and RSPV ostium (RSPV-SVC distance). RESULTS: A total of 97 patients (CB, n = 50 vs. RFB, n = 47) were included, with similar baseline characteristics between both groups. A significant HR increase postablation (ΔHR ≥ 15 bpm) occurred in a total of 37 patients (38.1%), without difference in number of patients between both thermal ablation technologies (CB, 19 [51%]), RFB, 18 [49%]). Independent predictors for increased HR were RSPV-SVC distance (odds ratio [OR]: 0.49, CI: 0.34-0.71, p value < .001), and age (OR: 0.94, CI: 0.89-0.98, p value = .003). CONCLUSIONS: Thermal balloon-based PV isolation influences the CANS through its effect on the RAGP, especially in younger patients and patients with shorter RSPV-SVC distance.

Catheter ablation as an adjunctive therapy to ICD implantation in Brugada syndrome.

BACKGROUND: Brugada Syndrome (BrS) is a life-threatening cardiac arrhythmia disorder associated with an increased risk ventricular arrhythmias (VAs) and sudden cardiac death (SCD). Current management primarily relies on implantable cardioverter-defibrillators (ICDs), but patients may experience ICD shocks. Catheter ablation (CA) has emerged as a potential intervention to target the arrhythmogenic substrate. This systematic review aims to evaluate the safety and efficacy of catheter ablation in BrS patients. METHODS AND RESULTS: Studies with BrS patients undergoing catheter ablation for VAs were included. 14 studies that involved a total population of 709 BrS patients, with catheter ablation performed in 528 of them, were included. Catheter ablation resulted in non-inducibility of VAs in 91% (95% CI: 83-99, I2 = 76%) and resolution of Type 1 ECG Brugada pattern in 88% (95% CI: 81-96.2, I2 = 91%) of the patients. After a mean follow-up of 30.7 months, 87% (95% CI: 80-94, I2 = 82%) of patients remained free from VAs. The incidence of VAs during follow-up was significantly lower in the ablation cohort in comparison to the group receiving only ICD therapy (OR = 0.03, 95% CI: 0.01-0.12, I2 = 0%). CONCLUSION: Catheter ablation shows potential as a therapeutic approach to reduce VAs and improve outcomes in BrS patients. While further research with long follow-up period is required to confirm these findings, it represents a valuable tool as an add-on intervention to ICD implantation in BrS patients with high burden of VAs.Protocol registration: CRD42024506439.

Predicting and Recognizing Drug-Induced Type I Brugada Pattern Using ECG-Based Deep Learning.

BACKGROUND: Brugada syndrome (BrS) has been associated with sudden cardiac death in otherwise healthy subjects, and drug-induced BrS accounts for 55% to 70% of all patients with BrS. This study aims to develop a deep convolutional neural network and evaluate its performance in recognizing and predicting BrS diagnosis. METHODS AND RESULTS: Consecutive patients who underwent ajmaline testing for BrS following a standardized protocol were included. ECG tracings from baseline and during ajmaline were transformed using wavelet analysis and a deep convolutional neural network was separately trained to (1) recognize and (2) predict BrS type I pattern. The resultant networks are referred to as BrS-Net. A total of 1188 patients were included, of which 361 (30.3%) patients developed BrS type I pattern during ajmaline infusion. When trained and evaluated on ECG tracings during ajmaline, BrS-Net recognized a BrS type I pattern with an AUC-ROC of 0.945 (0.921-0.969) and an AUC-PR of 0.892 (0.815-0.939). When trained and evaluated on ECG tracings at baseline, BrS-Net predicted a BrS type I pattern during ajmaline with an AUC-ROC of 0.805 (0.845-0.736) and an AUC-PR of 0.605 (0.460-0.664). CONCLUSIONS: BrS-Net, a deep convolutional neural network, can identify BrS type I pattern with high performance. BrS-Net can predict from baseline ECG the development of a BrS type I pattern after ajmaline with good performance in an unselected population.

SCN5A gene variants and arrhythmic risk in Brugada syndrome: An updated systematic review and meta-analysis.

BACKGROUND: A rare gene variant in SCN5A can be found in approximately 20%-25% of patients with Brugada syndrome (BrS). OBJECTIVE: The aim of this systematic review and meta-analysis was to evaluate the differences in clinical characteristics of BrS patients with and without SCN5A rare variants and the prognostic role of SCN5A for ventricular arrhythmias in BrS. METHODS: PubMed and Cochrane Central Register of Controlled Trials (CENTRAL) were systematically searched from inception to January 2024 to identify all relevant studies. Studies were analyzed if they included patients diagnosed with BrS in whom genetic testing for SCN5A variants was performed and arrhythmic outcomes were reported. RESULTS: A total of 17 studies with 3568 BrS patients, of whom 3030 underwent genetic testing for SCN5A variants, fulfilled the eligibility criteria and were included. Compared with SCN5A- patients, SCN5A+ BrS patients more frequently had spontaneous type 1 electrocardiogram, history of syncope, and documented arrhythmias. Furthermore, higher PQ and QRS intervals in SCN5A+ BrS patients compared with SCN5A- have been found. The pooled analysis demonstrated a significant association between the presence of SCN5A rare variants in BrS patients and the risk of major arrhythmic events, with a pooled odds ratio of 2.14 (95% confidence interval, 1.53-2.99; I2 = 29%). CONCLUSION: SCN5A+ BrS patients showed a worse clinical phenotype compared with SCN5A-. The pooled analysis demonstrated a significant association between SCN5A+ mutation status and the risk of major arrhythmic events in BrS patients.

Pericarditis prophylactic therapy after sinus node-sparing hybrid ablation for inappropriate sinus tachycardia/postural orthostatic sinus tachycardia.

Background: Pericarditis is the most common complication following hybrid sinus node-sparing ablation for inappropriate sinus tachycardia (IST)/postural orthostatic tachycardia syndrome (POTS). Objective: The study sought to evaluate the association of prophylaxis therapy on the risk of symptomatic pericarditis following hybrid IST/POTS ablation. Methods: All consecutive patients undergoing to hybrid ablation of symptomatic IST/POTS refractory or intolerant to drugs were retrospectively analyzed. Pharmacological prophylaxis therapy was based on acetylsalicylic acid and colchicine started on the day of the ablation and continued for at least 3 months. The primary endpoint was occurrence of symptomatic pericarditis. The secondary endpoint was occurrence of pericarditis-related complications, including the following: duration of pericarditis >3 months, hospitalization for pericarditis, postpericardiectomy pleuro-pericarditis, and pericardiectomy. Results: A total of 220 patients undergone to hybrid IST/POTS ablation were included and 44 (20%) underwent prophylaxis therapy. Pericarditis occurred in 101 (45.9%) patients, with 97 (96%) in the first 5 days. At survival analysis, prophylaxis was associated with higher rate of freedom from pericarditis (81.9% vs 47.2%, log-rank P < .001). Pericarditis-related complications were low, occurring in 7 (3.2%) patients. There was no difference in pericarditis-related complications between the patients who underwent prophylaxis therapy and patients who did not. At Cox multivariate analysis, predictors of pericarditis were IST (vs POTS) (hazard ratio 0.61, 95% confidence interval0.39-0.99, P = .04) and prophylaxis therapy (hazard ratio 0.27, 95% confidence interval 0.13-0.55, P < .001). Conclusion: In a large cohort of patients undergoing hybrid ablation for IST/POTS, a prophylaxis therapy with acetylsalicylic acid and colchicine was associated with a lower rate of symptomatic pericarditis.

Genetic Testing in Brugada Syndrome: A 30-Year Experience.

BACKGROUND: A pathogenic/likely pathogenic variant can be found in 20% to 25% of patients with Brugada syndrome (BrS) and a pathogenic/likely pathogenic variant in SCN5A is associated with a worse prognosis. The aim of this study is to define the diagnostic yield of a large gene panel with American College of Medical Genetics and Genomics variant classification and to assess prognosis of SCN5A and non-SCN5A variants. METHODS: All patients with BrS, were prospectively enrolled in the Universitair Ziekenhuis Brussel registry between 1992 and 2022. Inclusion criteria for the study were (1) BrS diagnosis; (2) genetic analysis performed with a large gene panel; (3) classification of variants following American College of Medical Genetics and Genomics guidelines. Patients with a pathogenic/likely pathogenic variant in SCN5A were defined as SCN5A+. Patients with a reported variant in a non-SCN5A gene or with no reported variants were defined as patients with SCN5A-. All variants were classified as missense or predicted loss of function. RESULTS: A total of 500 BrS patients were analyzed. A total of 104 patients (20.8%) were SCN5A+ and 396 patients (79.2%) were SCN5A-. A non-SCN5A gene variant was found in 75 patients (15.0%), of whom, 58 patients (77.3%) had a missense variant and 17 patients (22.7%) had a predicted loss of function variant. At a follow-up of 84.0 months, 48 patients (9.6%) experienced a ventricular arrhythmia (VA). Patients without any variant had higher VA-free survival, compared with carriers of a predicted loss of function variant in SCN5A+ or non-SCN5A genes. There was no difference in VA-free survival between patients without any variant and missense variant carriers in SCN5A+ or non-SCN5A genes. At Cox analysis, SCN5A+ or non-SCN5A predicted loss of function variant was an independent predictor of VA. CONCLUSIONS: In a large BrS cohort, the yield for SCN5A+ is 20.8%. A predicted loss of function variant carrier is an independent predictor of VA.

Pulsed field ablation of the right superior pulmonary vein prevents vagal responses via anterior right ganglionated plexus modulation.

BACKGROUND: Pulsed field ablation (PFA) is selective for the myocardium. However, vagal responses and reversible effects on ganglionated plexi (GP) are observed during pulmonary vein isolation (PVI). Anterior-right GP ablation has been proven to effectively prevent vagal responses during radiofrequency-based PVI. OBJECTIVE: The purpose of this study was to test the hypothesis that PFA-induced transient anterior-right GP modulation when targeting the right superior pulmonary vein (RSPV) before any other pulmonary veins (PVs) may effectively prevent intraprocedural vagal responses. METHODS: Eighty consecutive paroxysmal atrial fibrillation patients undergoing PVI with PFA were prospectively included. In the first 40 patients, PVI was performed first targeting the left superior pulmonary vein (LSPV-first group). In the last 40 patients, RSPV was targeted first, followed by left PVs and right inferior PV (RSPV-first group). Heart rate (HR) and extracardiac vagal stimulation (ECVS) were evaluated at baseline, during PVI, and postablation to assess GP modulation. RESULTS: Vagal responses occurred in 31 patients (78%) in the LSPV-first group and 5 (13%) in the RSPV-first group (P <.001). Temporary pacing was needed in 14 patients (35%) in the LSPV-first group and 3 (8%) in the RSPV-first group (P = .003). RSPV isolation was associated with similar acute HR increase in the 2 groups (13 ± 11 bpm vs 15 ± 12 bpm; P = .3). No significant residual changes in HR or ECVS response were documented in both groups at the end of the procedure compared to baseline (all P >.05). CONCLUSION: PVI with PFA frequently induced vagal responses when initiated from the LSPV. Nevertheless, an RSPV-first approach promoted transient HR increase and reduced vagal response occurrence.

Zero fluoroscopy catheter ablation of premature ventricular contractions: a multicenter experience.

BACKGROUND: Catheter ablation has become an established treatment option for premature ventricular complexes (PVCs). The use of fluoroscopy exposes patients and medical staff to potentially harmful stochastic and deterministic effects of ionizing radiations. We sought to analyze procedural outcomes in terms of safety and efficacy using a "zero fluoroscopy" approach for catheter ablation of PVCs. METHODS: The present retrospective, multicenter, observational study included 131 patients having undergone catheter ablation of PVCs using "zero fluoroscopy" between 2019 and 2020 in four centers compared with another group who underwent the procedure with fluoroscopy. RESULTS: Median age was 51.0 ± 15.9 years old; males were 77 (58.8%). Among the study population, 26 (19.8%) had a cardiomyopathy. The most frequent PVC origin was right ventricular outflow tract (55%) followed by the left ventricle (16%), LVOT and cusps (13.7%), and aortomitral continuity (5.3%). Acute suppression of PVC was achieved in 127 patients (96.9%). At 12 months, a complete success was documented in 109 patients (83.2%), a reduction in PVC burden in 18 patients (13.7%), and a failure was recorded in four patients (3.1%). Only two minor complications occurred (femoral hematoma and arteriovenous fistula conservatively treated). CONCLUSIONS: The PVC ablation with a "zero" fluoroscopy approach appears to be a safe procedure with no major complications and good rates of success and recurrence in our multicenter experience.

Redo procedures after sinus node sparing hybrid ablation for inappropriate sinus tachycardia/postural orthostatic sinus tachycardia.

AIMS: A novel sinus node (SN) sparing hybrid ablation for inappropriate sinus node tachycardia (IST)/postural orthostatic tachycardia syndrome (POTS) has been demonstrated to be an effective and safe therapeutic option in patients with symptomatic drug-resistant IST/POTS. The aim of this study was to evaluate the long-term rate of redo procedures after hybrid IST ablation and procedural strategy, outcomes and safety of redo procedures. METHODS AND RESULTS: All consecutive patients from 2015 to 2023 were prospectively enrolled in the UZ Brussel monocentric IST/POTS registry. They were analysed if the following inclusion criteria were fulfilled: 1) diagnosis of IST or POTS, 2) symptomatic IST/POTS refractory or intolerant to drugs, and 3) hybrid SN sparing ablation performed. The primary endpoint was redo procedure. The primary safety endpoint was pacemaker (PM) implantation. A total of 220 patients undergone to hybrid IST ablation were included, 185 patients (84.1%) were treated for IST and 61 patients (27.7%) for POTS.After a follow-up of 73.3 ± 16.2 months, 34 patients (15.4%) underwent a redo. A total of 23 patients (67.6%) had a redo for IST recurrence and 11 patients (32.4%) for other arrhythmias. Pacemaker implantation was performed in 21 patients (9.5%). Nine patients (4.1%) had no redo procedure and experienced sick sinus syndrome requiring a PM. Twelve patients (5.4%) received a PM as a shared therapeutic choice combined with SN ablation procedure. CONCLUSION: In a large cohort of patients the long-term free survival from redo procedure after hybrid IST ablation was 84.6% with a low PM implantation rate.

Pulsed electric field, cryoballoon, and radiofrequency for paroxysmal atrial fibrillation ablation: a propensity score-matched comparison.

AIMS: Pulsed field ablation (PFA) has emerged as a novel, non-thermal energy source to selectively ablate cardiac tissue. We describe a multicentre experience on pulmonary vein isolation (PVI) via the pentaspline Farapulse™ PFA system vs. thermal-based technologies in a propensity score-matched population of paroxysmal atrial fibrillation (PAF) patients. METHODS AND RESULTS: Propensity score matching was adopted to compare PVI-only ablation outcomes via the Farawave™ system (Group PFA), cryoballoon (Group CRYO), or focal radiofrequency (Group RF) (PFA:CRYO:RF ratio = 1:2:2). Among 1572 (mean age: 62.4 ± 11.3 years; 42.5% females) PAF patients undergoing first time PVI with either PFA (n = 174), CRYO (n = 655), or RF (n = 743), propensity score matching yielded 174 PFA, 348 CRYO, and 348 RF patients. First-pass isolation was achieved in 98.8% of pulmonary veins (PVs) with PFA, 81.5% with CRYO, and 73.1% with RF (P < 0.001). Procedural and dwell times were significantly shorter with PFA, whereas the availability of a 3D mapping system led to a significant reduction in X-ray exposure with RF. Overall complication rates were 3.4% (n = 6) with PFA, 8.6% (n = 30) with CRYO, and 5.5% (n = 19) with RF (P = 0.052). The 1-year Kaplan-Meier estimated freedom from any atrial tachyarrhythmia was 79.3% with PFA, 74.7% with CRYO, and 72.4% with RF (log-rank P-value: 0.24). Among 145 repeat ablation procedures, PV reconnection rate was 19.1% after PFA, 27.5% after CRYO, and 34.8% after RF (P = 0.01). CONCLUSION: Pulsed field ablation contributed to significantly shorter procedural times. Follow-up data showed a similar arrhythmia freedom, although a higher rate of PV reconnection was documented in post-CRYO and post-RF redo procedures.