Siontis, Konstantinos C.

Abstract Background Vagally mediated syncope and functional bradyarrhythmias can cause recurrent symptoms, injury and a need for permanent pacing, yet standard therapies do not address the underlying autonomic reflex. Cardioneuroablation (CNA) targets this mechanism, but adoption has been limited by uncertainty about patient selection, procedural endpoints and durable outcomes. Methods We studied 95 consecutive patients with vagally mediated syncope (n=78) or functional bradyarrhythmia (n=17) who underwent CNA at a single center by a single lead operator under a uniform, prospectively maintained protocol. Extracardiac vagal stimulation (ECVS) was performed before and after ablation to confirm vagally mediated sinus or atrioventricular (AV) nodal responses and to verify their attenuation. Outcomes through 1 year included clinical recurrence, quality of life, pacing burden and pacemaker extraction. Results Before ablation, ECVS provoked sinus pauses in 95.8% of patients and AV block in 91.6%; after ablation, sinus pauses were abolished in every patient and residual AV block was present in 4.2%. One-year freedom from recurrent syncope and from bradyarrhythmia-related events was 93.8% and 94.1%. Syncope burden fell from a median of 2.7 episodes per year to none, and disease-specific quality of life improved substantially (P<0.001). Among patients with pre-existing devices, atrial pacing burden fell from a median of 22% to 0%. There were no strokes, deaths or myocardial infarctions. Conclusions In this single-center cohort, physiology-guided CNA was associated with durable symptom control, improved quality of life and reduced pacing across vagally mediated bradyarrhythmia syndromes. Multicenter controlled studies are needed to confirm these findings.

Abstract Aims Conduction system pacing (CSP) has emerged as a physiologic alternative to cardiac resynchronization therapy (CRT) with biventricular pacing (BiVP) in heart failure with reduced ejection fraction (HFrEF), yet its comparative effects remain uncertain. This meta-analysis sought to compare outcomes of CSP vs. BiVP in patients with HFrEF undergoing CRT. Methods and results MEDLINE, Embase, Scopus, and the Cochrane Database were searched through 4 May 2026. Randomized controlled trials (RCTs) were synthesized using random-effects meta-analysis. Thirteen RCTs including 1320 participants were analysed (657 CSP, 663 BiVP). Conduction system pacing was associated with a lower risk of the composite of hospitalization for heart failure (HHF) or all-cause mortality compared with BiVP (46 vs. 83 events; odds ratio [OR] 0.51, 95% confidence interval [CI] 0.28–0.93). No significant differences were observed for HHF alone (OR 0.68, 95% CI 0.36–1.27) or all-cause mortality (OR 0.75, 95% CI 0.36–1.58). Conduction system pacing was associated with greater improvement in the 6-min walk distance (mean difference [MD] 21.53 m, 95% CI 4.33–38.73) and New York Heart Association functional class (standardized mean difference [SMD] −0.27, 95% CI −0.47 to −0.07), but not quality of life. Conduction system pacing also reduced QRS duration compared with BiVP (MD −10.94 ms, 95% CI −17.55 to −4.34), with no significant differences in left ventricular ejection fraction, left ventricular end-systolic volume, overall pacing threshold, total procedure time, fluoroscopy time, any complication, or reintervention. Conclusion In patients with HFrEF undergoing CRT, CSP is associated with lower composite risk of HHF or all-cause mortality compared with BiVP. Conduction system pacing is also associated with improved functional capacity, without significant differences in safety or procedural outcomes.

Abstract Background Arrhythmogenic mitral valve prolapse (AMVP) is increasingly recognized as a cause of sustained ventricular arrhythmias (VA) and sudden cardiac death. Although prior studies have identified clinical and imaging risk markers in AMVP, it remains unclear whether the arrhythmogenic phenotype differs between women and men. Purpose To investigate sex-specific differences in clinical profiles, structural substrates, and arrhythmia presentations in patients with AMVP who experienced sustained VA. Methods We conducted a sex-based sub-analysis of a multicenter cohort (35 centers from 15 countries) of patients with AMVP and sustained VA. Participants were grouped by sex and by initial arrhythmia type (sustained monomorphic ventricular tachycardia [SMVT] vs ventricular fibrillation [VF]). Data collected included clinical history, ECG findings, echocardiographic measurements, and cardiac MRI (CMR) markers, such as late gadolinium enhancement (LGE) patterns and mitral annular disjunction (MAD). These factors were compared across groups. Results The study comprised 129 women (57%) and 96 men (43%). Women were diagnosed at younger ages (39±16 years vs. 49±16 years, p&lt;0.03) and had more frequently a family history of MVP (22% vs 10%, p=0.027). MAD was significantly more common in women (66% vs 48%, p=0.015) while LGE was more frequently observed in men than women (N=39 (72%) vs N=41 (53%), p=0.028), with no significant regional patterns (myocardial and/or papillary muscle). ECG T-wave inversion (p=0.627), PVC burden (p&gt;0.03) and arrhythmia types were similar in men and women. However, stress was a more often commonly recognized as the initiating trigger for VA in men than in women (38% [N=24] vs. 18% [N=18], p&lt;0.05). The overwhelming majority of VA were initiated by PVCs in both sexes with no differences in the initiating mechanisms. Conclusion In patients with AMVP presenting with sustained VA, the arrhythmic phenotype and initiating mechanisms are similar between sexes, although stress was a significantly stronger trigger for VA in men. Women more often exhibited MAD, whereas LGE was more frequent in men. These findings suggest that structural and tissue-based markers, rather than sex alone, contribute to the development of malignant arrhythmias in AMVP.

ABSTRACT Background Superior vena cava isolation (SVCI) is performed as an adjunct to pulmonary vein isolation (PVI) for atrial fibrillation, yet whether an empiric or trigger‐guided strategy is preferable remains uncertain. Prior meta‐analyses have been largely restricted to index procedures in paroxysmal AF and have not explicitly stratified by ablation strategy. We sought to address these gaps through a systematic review of available randomized evidence. Methods Major databases were searched through November 2025 for RCTs comparing PVI+SVCI versus PVI alone. Trials were stratified by strategy: empiric SVCI (performed irrespective of SVC ectopy) or trigger‐guided SVCI (performed only upon demonstrated SVC triggers). The primary outcome was atrial tachyarrhythmia recurrence (≥30 s) beyond the blanking period. Random‐effects models, pre‐specified subgroup analyses, meta‐regression, and GRADE certainty assessment were performed. Results Eight RCTs ( n = 1231) were included; most enrolled paroxysmal AF, while two incorporated non‐paroxysmal AF subtypes and one evaluated repeat ablation procedures. Overall, SVCI+PVI significantly reduced recurrence versus PVI alone (97/604 vs. 135/627; RR 0.77, 95% CI 0.61–0.97; p = 0.03; I 2 = 0%). On stratified analysis, empiric SVCI demonstrated a significant recurrence reduction (RR 0.70, 95% CI 0.53–0.92; p = 0.01; I 2 = 0%), while trigger‐guided SVCI did not reach statistical significance (RR 0.80, 95% CI 0.37–1.74; p = 0.57; I 2 = 52%). In paroxysmal AF ( n = 1038), adjunctive SVCI significantly reduced recurrence compared with PVI alone (RR 0.68, 95% CI 0.52–0.90; p = 0.01; I 2 = 0%). Fluoroscopy time was longer with SVCI; total procedure duration was comparable. Major complications were infrequent but numerically higher with SVCI+PVI (15/604 vs. 7/627; RR 1.96, 95% CI 0.87–4.38; p = 0.10). Meta‐regression identified no significant effect modifiers. GRADE certainty was high for overall and empiric analyses, and moderate for trigger‐guided SVCI. Conclusions Empiric SVCI significantly reduced AT/AF recurrence as an adjunct to PVI, while trigger‐guided SVCI did not demonstrate a significant benefit. These findings suggest SVC isolation confers benefit independent of prior trigger documentation, supporting the role of empiric SVCI as an adjunct to AF ablation.

ABSTRACT Background Atrial fibrillation (AF) is common in patients with hypertrophic cardiomyopathy (HCM) and is associated with increased morbidity, heart failure (HF) exacerbations, and adverse long‐term outcomes. Although catheter ablation is an established rhythm‐control strategy, data comparing its long‐term clinical outcomes with anti‐arrhythmic drug (AAD) therapy in patients with HCM remain limited. Objective To compare long‐term clinical outcomes of catheter ablation versus medical therapy with AADs in patients with HCM and AF. Methods We conducted a retrospective cohort study using the TriNetX Research Network, a global federated database of electronic health records. Adult patients with HCM and AF between January 2010 and December 2020 were identified and stratified according to treatment with catheter ablation or AAD therapy. Outcomes included all‐cause mortality, HF exacerbations, AAD‐related adverse events, all‐cause hospitalization, ischemic stroke, repeat ablation, need for cardioversion, need for long‐term AAD use, and atrioventricular nodal ablation. A 1:1 propensity score matching (PSM) analysis was performed to balance baseline characteristics. Kaplan–Meier survival analysis and Cox proportional hazards models were used to estimate hazard ratios (HRs). Results After PSM, 3144 patients were included (1572 in each cohort) with a mean follow‐up of approximately 3.4 years. Catheter ablation was associated with lower all‐cause mortality compared with AAD therapy (9.5% vs. 14.8%; HR: 0.60; 95% CI: 0.49–0.74; p < 0.001). Ablation was also associated with reduced risk of HF exacerbations (38.4% vs. 43.3%; HR: 0.79; 95% CI: 0.71–0.88; p < 0.001) and fewer AAD‐related adverse events (8.4% vs. 11.2%; HR: 0.71; 95% CI: 0.55–0.93; p = 0.011). Rates of all‐cause hospitalization (HR: 0.93; p = 0.11) and ischemic stroke (HR: 0.78; p = 0.10) were similar between groups. Conclusion In this large real‐world cohort of patients with HCM and AF, catheter ablation was associated with lower mortality, reduced HF hospitalizations, and decreased AAD therapy‐related adverse events, as compared with medical therapy. These findings suggest that catheter ablation may provide meaningful clinical benefits in selected patients with HCM and AF, although prospective studies are needed to confirm these observations.

BACKGROUND: Radiofrequency (RF) ablation of premature ventricular complexes (PVCs) originating from the left ventricular summit may be unsuccessful, highlighting the need for alternative approaches. We aimed to assess the efficacy and safety of a novel dual-modality focal catheter in treating left ventricular summit PVCs in patients who had failed previous RF ablation. METHODS: Patients were prospectively enrolled and underwent a redo ablation procedure using an irrigated, contact-force sensing, dual-modality focal catheter (TactiFlex Duo, Abbott) under compassionate use indication. The ablation strategy, including the choice of energy modality (monopolar pulsed field [PF], RF, or both), was left to the operator’s discretion. Safety assessments included serial biomarkers, renal function, and CMR within 36 hours. Efficacy was defined as ≥80% reduction in PVC burden with symptom resolution at 3-month follow-up. RESULTS: Six consecutive patients (4 men; mean age, 53.8±15 years) with symptomatic left ventricular summit PVCs and a prior failed RF ablation (range, 1–2) were prospectively enrolled. All PVCs had an inferior axis, with a left bundle V1 morphology observed in 4 of 6 cases (mean burden, 30.1±5.3%). Acute suppression of PVCs was achieved in all cases. Acute suppression with a single PF application in the great cardiac vein-anterior interventricular vein occurred in 2 patients, while 3 patients required additional RF, PF, or combined RF+PF applications at adjacent sites. One patient with an inaccessible great cardiac vein-anterior interventricular vein was successfully treated in the left ventricular outflow tract with RF+PF application. Transient, reversible left anterior descending vasospasm was observed during PF delivery in 2 of 5 cases that underwent PF application adjacent to a coronary artery, despite pretreatment with intracoronary nitroglycerin without ECG or hemodynamic sequelae. All patients had durable suppression of PVCs at follow-up. CONCLUSIONS: In its first human application, dual-modality ablation was feasible and effective for refractory left ventricular summit PVCs. Transient coronary vasospasm occurred, though it was reversible and without acute clinical consequences.

ABSTRACT Introduction Cardiac myosin inhibitors (CMIs) improve hemodynamics and symptoms in hypertrophic cardiomyopathy (HCM), but recent real‐world data have raised concerns regarding an increased risk of atrial fibrillation (AF). We sought to reassess AF risk using randomized controlled trial (RCT) evidence and to contextualize discrepancies with observational reports. Methods and Results We performed a systematic review and random‐effects meta‐analysis of RCTs evaluating the effect of CMIs on incident AF in HCM. MEDLINE, Scopus, and CENTRAL were searched through November 25, 2025. Eight RCTs ( n = 1581) comparing mavacamten or aficamten with placebo or active control were included. Event counts were pooled as risk ratios (RRs) with 95% confidence intervals (CIs). CMIs were not associated with increased AF risk (RR 1.11, 95% CI 0.62–1.98; heterogeneity I 2 = 0%). No differences were observed between mavacamten and aficamten, with consistent findings across HCM subtypes (obstructive and non‐obstructive). Importantly, most trials (7/8) excluded patients with uncontrolled, persistent, or permanent AF, five excluded paroxysmal AF at screening, and one excluded any AF history. Baseline left atrial enlargement was generally in the mild to moderate range across trials, suggesting limited representation of high‐risk AF phenotypes. Conclusion Randomized evidence to date does not demonstrate an increased AF risk with CMIs. Differences between RCT populations and real‐world cohorts, including restrictive AF eligibility criteria, lower baseline atrial remodeling, and limited rhythm surveillance may explain discordant observational findings and highlight the need for longitudinal monitoring in clinical practice.

Background Multimorbidity is common in patients with atrial fibrillation (AF); however, the impact of the number and type of comorbid conditions on outcomes remains uncertain. Methods This cohort study included patients with new‐onset AF from a Midwest region between 2013 and 2017. Eighteen chronic conditions at the time of AF were classified into groups: cardiometabolic, other somatic, and mental health. Cox regression determined associations between the number of each condition type with death, ischemic stroke/transient ischemic attack, and congestive heart failure, stratified by age. Results Among 16 509 patients with AF (mean age, 74 years; 43% women), the mean number of cardiometabolic, other somatic, and mental health conditions was 2.7, 1.4, and 0.5, respectively. The number and type of conditions had a varying impact on outcomes and differed by age. A higher number of cardiometabolic conditions were associated with increased risk of death within 90 days only in people aged ≥85 years (≥4 conditions versus 0: hazard ratio [HR], 1.74 [95% CI, 1.05–2.87]), whereas for death after 90 days, associations were strongest in the youngest age group (<65 years: HR, 1.83 [95% CI, 1.35–2.46]; 65–74 years: HR, 1.34 [95% CI, 1.04–1.73]; 75–84 years: HR, 1.32 [95% CI, 1.09–1.60]; ≥85 years: HR, 1.14 [95% CI, 0.96–1.35]). Associations with outcomes were generally strongest in the youngest age group and attenuated with older age for higher number of other somatic conditions, whereas the pattern was less consistent for mental health conditions. Conclusions Along with cardiometabolic‐related conditions, other somatic and mental health conditions are important predictors of outcomes in AF, with effects differing by age, and should be considered when caring for these patients.