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.

Sequential Unipolar Biventricular Pulsed Field Ablation for Refractory Intramural Septal Ventricular Tachycardia.

Catheter ablation of septal ventricular tachycardia (VT) is challenging. Pulsed field ablation is a promising technology, potentially reaching deep substrates. We report the first sequential unipolar biventricular pulsed field ablation targeting refractory septal VT. Besides, we illustrate the importance of searching underlying cardiomyopathy in patients with recurrent multiple morphology VTs and normal magnetic resonance imaging.

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.

Pre- and post-procedural cardiac imaging (computed tomography and magnetic resonance imaging) in electrophysiology: a clinical consensus statement of the European Heart Rhythm Association and European Association of Cardiovascular Imaging of the European Society of Cardiology.

Imaging using cardiac computed tomography (CT) or magnetic resonance (MR) imaging has become an important option for anatomic and substrate delineation in complex atrial fibrillation (AF) and ventricular tachycardia (VT) ablation procedures. Computed tomography more common than MR has been used to detect procedure-associated complications such as oesophageal, cerebral, and vascular injury. This clinical consensus statement summarizes the current knowledge of CT and MR to facilitate electrophysiological procedures, the current value of real-time integration of imaging-derived anatomy, and substrate information during the procedure and the current role of CT and MR in diagnosing relevant procedure-related complications. Practical advice on potential advantages of one imaging modality over the other is discussed for patients with implanted cardiac rhythm devices as well as for planning, intraprocedural integration, and post-interventional management in AF and VT ablation patients. Establishing a team of electrophysiologists and cardiac imaging specialists working on specific details of imaging for complex ablation procedures is key. Cardiac magnetic resonance (CMR) can safely be performed in most patients with implanted active cardiac devices. Standard procedures for pre- and post-scanning management of the device and potential CMR-associated device malfunctions need to be in place. In VT patients, imaging-specifically MR-may help to determine scar location and mural distribution in patients with ischaemic and non-ischaemic cardiomyopathy beyond evaluating the underlying structural heart disease. Future directions in imaging may include the ability to register multiple imaging modalities and novel high-resolution modalities, but also refinements of imaging-guided ablation strategies are expected.

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.

Practical approach for atrial cardiomyopathy characterization in patients with atrial fibrillation.

Atrial fibrillation (AF) causes progressive structural and electrical changes in the atria that can be summarized within the general concept of atrial remodeling. In parallel, other clinical characteristics and comorbidities may also affect atrial tissue properties and make the atria susceptible to AF initiation and its long-term persistence. Overall, pathological atrial changes lead to atrial cardiomyopathy with important implications for rhythm control. Although there is general agreement on the role of the atrial substrate for successful rhythm control in AF, the current classification oversimplifies clinical management. The classification uses temporal criteria and does not establish a well-defined strategy to characterize the individual-specific degree of atrial cardiomyopathy. Better characterization of atrial cardiomyopathy may improve the decision-making process on the most appropriate therapeutic option. We review current scientific evidence and propose a practical characterization of the atrial substrate based on 3 evaluation steps starting with a clinical evaluation (step 1), then assess outpatient complementary data (step 2), and finally include information from advanced diagnostic tools (step 3). The information from each of the steps or a combination thereof can be used to classify AF patients in 4 stages of atrial cardiomyopathy, which we also use to estimate the success on effective rhythm control.

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.

Lower rate of major bleeding in very high risk patients undergoing left atrial appendage occlusion: A propensity score-matched comparison with direct oral anticoagulation.

BACKGROUND: Long-term oral anticoagulation is the mainstay therapy for thromboembolic (TE) prevention in patients with atrial fibrillation. However, left atrial appendage occlusion (LAAO) could be a safe alternative to direct oral anticoagulants (DOACs) in patients with a very high TE risk profile. OBJECTIVE: The purpose of this study was to compare the safety and efficacy of LAAO vs DOACs in patients with atrial fibrillation at very high stroke risk (CHA2DS2-VASc [congestive heart failure, hypertension, age ≥ 75 years, diabetes mellitus, prior stroke or transient ischemic attack or thromboembolism, vascular disease, age 65-74 years, sex category] score ≥ 5). METHODS: Data from patients with CHA2DS2-VASc score ≥ 5 were extracted from a prospective multicenter database. To attenuate the imbalance in covariates between groups, propensity score matching was used (covariates: CHA2DS2-VASc and HAS-BLED [hypertension, abnormal renal or liver function, stroke, bleeding, labile international normalized ratio, elderly, drugs or alcohol] scores), which resulted in a matched population of 277 patients per group. The primary end point was a composite of cardiovascular death, TE events, and clinically relevant bleeding during follow-up. RESULTS: Of 2381 patients, 554 very high risk patients were included in the study (mean age 79 ± 7 years; CHA2DS2-VASc score 5.8 ± 0.9; HAS-BLED score 3.0 ± 0.9). The mean follow-up duration was 25 ± 11 months. A higher incidence of the composite end point was documented with DOACs compared with LAAO (14.9 events per 100 patient-years in the DOAC group vs 9.4 events per 100 patient-years in the LAAO group; P = .03). The annualized clinically relevant bleeding risk was higher with DOACs (6.3% vs 3.2%; P = .04), while the risk of TE events was not different between groups (4.1% vs 3.2%; P = .63). CONCLUSION: In high-risk patients, LAAO had a similar stroke prevention efficacy but a significantly lower risk of clinically relevant bleeding when compared with DOACs. The clinical benefit of LAAO became significant after 18 months of follow-up.

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.

Posterior wall isolation via a multi-electrode radiofrequency balloon catheter: feasibility, technical considerations, endoscopic findings and comparison with cryoballoon technologies.

BACKGROUND: Posterior wall (PW) isolation is an important adjunctive ablation target in patients with non-paroxysmal atrial fibrillation (AF). Traditionally performed with point-by-point radiofrequency (RF) ablation, PW isolation has also been performed with different cryoballoon technologies. We aimed at assessing the feasibility of PW isolation with the novel RF balloon catheter Heliostar™ (Biosense Webster, CA, USA). METHODS: We prospectively enrolled 32 consecutive patients with persistent AF scheduled for first-time ablation with the Heliostar™ device. Procedural data were compared with those from 96 consecutive persistent AF patients undergoing pulmonary vein (PV) plus PW isolation with a cryoballoon device. The ratio RF balloon/cryoballoon was 1:3 for each operator involved in the study, aiming at avoiding any imbalance related to different experience. RESULTS: Single-shot PV isolation was documented in a significantly higher number of cases with the RF balloon technology compared to cryoballoon ablation (89.8% vs. 81.0%; p = 0.02, respectively). PW isolation was achieved with a similar number of balloon applications between the two groups (11 ± 4 with the RF balloon versus 11 ± 2 with the cryoballoon; p = 0.16), but in a significantly shorter time among RF balloon patients (228 ± 72 s versus 1274 ± 277 s with cryoballoon; p < 0.001). Primary safety endpoint occurred in none of the RF balloon patients versus 5 (5.2%) patients in the cryoballoon group (p = 0.33). Primary efficacy endpoint was achieved in all (100%) RF balloon patients versus 93 (96.9%) cryoballoon ones (p = 0.57). Oesophageal endoscopy did not show any signs of thermal lesions in RF balloon patients with luminal temperature rise. CONCLUSIONS: RF balloon-based PW isolation was safe and promoted shorter procedure times compared to similar cryoballoon-based ablation procedures.

Anticoagulation with edoxaban in patients with long atrial high-rate episodes ≥24†h.

BACKGROUND AND AIMS: Patients with long atrial high-rate episodes (AHREs) ≥24 h and stroke risk factors are often treated with anticoagulation for stroke prevention. Anticoagulation has never been compared with no anticoagulation in these patients. METHODS: This secondary pre-specified analysis of the Non-vitamin K antagonist Oral anticoagulants in patients with Atrial High-rate episodes (NOAH-AFNET 6) trial examined interactions between AHRE duration at baseline and anticoagulation with edoxaban compared with placebo in patients with AHRE and stroke risk factors. The primary efficacy outcome was a composite of stroke, systemic embolism, or cardiovascular death. The safety outcome was a composite of major bleeding and death. Key secondary outcomes were components of these outcomes and electrocardiogram (ECG)-diagnosed atrial fibrillation. RESULTS: Median follow-up of 2389 patients with core lab-verified AHRE was 1.8 years. AHRE ≥24 h were present at baseline in 259/2389 patients (11%, 78 ± 7 years old, 28% women, CHA2DS2-VASc 4). Clinical characteristics were not different from patients with shorter AHRE. The primary outcome occurred in 9/132 patients with AHRE ≥24 h (4.3%/patient-year, 2 strokes) treated with anticoagulation and in 14/127 patients treated with placebo (6.9%/patient-year, 2 strokes). Atrial high-rate episode duration did not interact with the efficacy (P-interaction = .65) or safety (P-interaction = .98) of anticoagulation. Analyses including AHRE as a continuous parameter confirmed this. Patients with AHRE ≥24 h developed more ECG-diagnosed atrial fibrillation (17.0%/patient-year) than patients with shorter AHRE (8.2%/patient-year; P < .001). CONCLUSIONS: This hypothesis-generating analysis does not find an interaction between AHRE duration and anticoagulation therapy in patients with device-detected AHRE and stroke risk factors. Further research is needed to identify patients with long AHRE at high stroke risk.

Coronary artery disease in atrial fibrillation ablation: impact on arrhythmic outcomes.

AIMS: Catheter ablation (CA) is an established treatment for atrial fibrillation (AF). A computed tomography (CT) may be performed before ablation to evaluate the anatomy of pulmonary veins. The aim of this study is to investigate the prevalence of patients with coronary artery disease (CAD) detected by cardiac CT scan pre-ablation and to evaluate the impact of CAD and revascularization on outcomes after AF ablation. METHODS AND RESULTS: All consecutive patients with AF diagnosis, hospitalized at Universitair Ziekenhuis Brussel, Belgium, between 2015 and 2019, were prospectively screened for enrolment in the study. Inclusion criteria were (i) AF diagnosis, (ii) first procedure of AF ablation with cryoballoon CA, and (iii) contrast CT scan performed pre-ablation. A total of 576 consecutive patients were prospectively included and analysed in this study. At CT scan, 122 patients (21.2%) were diagnosed with CAD, of whom 41 patients (7.1%) with critical CAD. At survival analysis, critical CAD at CT scan was a predictor of atrial tachyarrhythmia (AT) recurrence during the follow-up, only in Cox univariate analysis [hazard ratio (HR) = 1.79] but was not an independent predictor in Cox multivariate analysis. At Cox multivariate analysis, independent predictors of AT recurrence were as follows: persistent AF (HR = 2.93) and left atrium volume index (HR = 1.04). CONCLUSION: In patients undergoing CT scan before AF ablation, critical CAD was diagnosed in 7.1% of patients. Coronary artery disease and revascularization were not independent predictors of recurrence; thus, in this patient population, AF ablation should not be denied and can be performed together with CAD treatment.

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.

Atrial fibrillation cycle-length (AF-CL) inside the pulmonary veins predicts paroxysmal AF ablation success- the INDUCE-AF study.

BACKGROUND: A novel method to measure atrial fibrillation cycle length (AF-CL) was recently described, based on the average of 10 consecutive signals (FARS10). FARS10 accurately identified pulmonary vein isolation (PVI)-responders among patients with persistent AF. Whether this method is applicable to patients with paroxysmal AF is unknown. OBJECTIVE: The aim of this study is to evaluate the prognostic value of FARS10 measurements in patients with paroxysmal AF. METHODS AND RESULTS: We enrolled paroxysmal AF patients undergoing PVI in a prospective multicenter study. After AF induction with a standardized protocol, the AF-CL was measured using FARS-10 method. The primary endpoint was AF/AT-recurrence. One-hundred and four patients were included (61 ± 14 years, 25% females). After a mean follow-up of 12 ± 4 months, AF/AT recurrence rate was 20%. The fastest PV CL (fPV-CL) was independently associated with the primary endpoint at multivariate analysis (HR 1.02, p < 0.001). Every 10 ms increase in fPV-CL, AF recurrences increased by 20%. The value of 160 ms was found to be the optimal cut-off (specificity 81%, sensitivity 76%). Patients with fPV-CL < 160 ms experienced lower AF recurrences as compared to patients with fPV-CL > 160 ms (8% vs. 32% at 1 year; HR = 0.17, p < 0.001). Progression to persistent AF was observed in 13% of patients with fPV-CL > 160 ms. CONCLUSION: fPV-CL measured with the FARS-10 method accurately predicts PVI success in paroxysmal AF patients undergoing PVI. Patients with slow PV activity (fPV-CL > 160 ms) experience higher AF recurrence rate after PVI and more frequent progression to persistent AF. In 104 patients with paroxysmal atrial fibrillation (AF) undergoing AF ablation, AF was induced at the beginning of the procedure. Pulmonary vein activity was measured using FARS10 measurement (10 consecutive fastest atrial repetitive similar morphology signals). The value of 160 ms was found to be the best cut-off to discriminate outcomes. At 1-year follow-up, patients with fast veins (< 160 ms) experienced significantly fewer AF recurrences as compared to patients with slow veins (> 160 ms). PV activity measured with FARS10 method accurately discriminates pulmonary vein isolation responders, in patients with paroxysmal AF. ABBREVIATIONS: AF atrial fibrillation, AT atrial tachycardia, CL cycle length, FARS10: 10 consecutive fastest atrial repetitive similar morphology signal, fPV fastest pulmonary vein, HR hazard ratio, ms milliseconds.

Dynamic changes of left atrial substrate over time following pulmonary vein isolation: the Progress-AF study.

AIMS: Little is known about dynamic changes of the left atrial (LA) substrate over time in patients with atrial fibrillation (AF). This study aims to evaluate substrate changes following pulmonary vein isolation (PVI). METHODS AND RESULTS: In our prospective observational study, consecutive patients undergoing first PVI-only and redo ablation were included. High-density maps of the two procedures were compared. Progression or regression was diagnosed if a significant concordant decrease or increase in bipolar voltages in ≥2 segments was observed, respectively. In 28 patients (61.2 ± 9.5 years, 39% female, 53.5% persistent AF), 111.013 voltage points from 56 high-density LA maps (1.982 points/patient) were analysed. Comparing the high-density maps of the first and second procedures, in the progression group (17 patients, 61%), there was a decrease in global (-35%, P < 0.001) and all regional voltages. In the regression group (11 patients, 39%), there was an increase in global (+43%, P < 0.001) and regional voltages. Comparing the progression with the regression group, the area of low-voltage zone (LVZ) increased (+3.5 vs. -4.5 cm2, P < 0.001) and LA activation time prolonged (+8.0 vs. -9.1 ms, P = 0.005). Baseline clinical parameters did not predict progression or regression. In patients with substrate progression, pulmonary veins (PVs) were more frequently isolated (P = 0.02) and the AF pattern at recurrence was more frequently persistent (P = 0.005). CONCLUSION: Our study describes bidirectional dynamic properties of the LA substrate with concordant either progressive or regressive changes. Regression occurs with reduced AF burden after the first procedure, while progression is associated with persistent AF recurrence despite durable PV isolation. The dynamic nature of LA substrate poses questions about LVZ-based ablation strategies.

Quantitative assessment of transient autonomic modulation after single-shot pulmonary vein isolation with pulsed-field ablation.

INTRODUCTION: Pulmonary vein isolation (PVI) with thermal energy is characterized by concomitant ablation of the surrounding ganglionated plexi (GP). Pulsed-field ablation (PFA) selectively targets the myocardium and seems associated with only negligible effects on the autonomic nervous system (ANS). However, little is known about the dynamic effects of PFA on the GP immediately after PVI. This study sought to investigate the degree and acute vagal modulation induced by the FarapulseTM PFA system during PVI compared with single-shot thermal ablation. METHODS: A total of 76 patients underwent first-time PVI with either FarapulseTM PFA (PFA group, n = 40) or cryoballoon ablation (thermal ablation group, n = 36) for paroxysmal atrial fibrillation (AF). The effect on the ANS in the two groups was assessed before and after PVI with extracardiac vagal stimulation (ECVS). To capture any transient effects of PFA on the ANS, in a subgroup of PFA patients ECVS was repeated at three predefined timepoints: (1) before PVI (T0); (2) immediately after PVI (T1); and (3) 10 min after the last energy application (T2). RESULTS: Despite similar baseline values, the vagal response induced by ECVS after PVI almost disappeared in the thermal ablation group but persisted in the PFA group (thermal group: 840 [706-1090] ms, p < .001 compared to baseline; PFA group: 11 466 [8720-12 293] ms, p = .70 compared to baseline). Intraprocedural vagal reactions (defined as RR increase >50%, transitory asystole, or atrioventricular block) occurred more frequently with PFA than thermal ablation (70% vs. 28%, p = .001). Moreover, heart rate 24 h post-PVI increased more with thermal ablation than with PFA (16.5 ± 9.0 vs. 2.6 ± 6.1 beats/min, p < .001). In the subgroup of PFA patients undergoing repeated ANS modulation assessment (n = 11), ECVS demonstrated that PFA determined a significant acute suppression of the vagal response immediately after PVI (p < .001 compared to baseline), which recovered almost completely within 10 min. CONCLUSION: PVI with the FarapulseTM PFA system is associated with only transitory and short-lasting vagal effects on the ANS which recover almost completely within a few minutes after ablation. The impact of this phenomenon on AF outcome needs to be further investigated.