Recently, catheters incorporating both contact force (CF) sensing and local impedance (LI) measurement-an indicator of tissue temperature-have become clinically available. The present study aims to evaluate the efficacy of superior vena cava isolation (SVCI) using this catheter and to investigate the characteristics of impedance during the procedure. This retrospective study included 64 patients undergoing initial SVCI using the StablePoint catheter (40 W, CF 10-20 g, 8-10 s). We analyzed the success rate of SVCI and impedance data collected from 1 402 ablation points, with particular attention to the dynamics of LI and generator impedance (GI). First-pass isolation was achieved in all cases without complications such as phrenic nerve or sinus node injury. The LI drop was significantly greater and faster than the GI drop in all segments. The 90% decay time of LI was consistently 5-6 s, suggesting effective lesion formation during the resistive heating phase. LI provides a more reliable and localized indicator of tissue response than GI. The temporal profile of LI supports its utility in guiding safe and effective lesion delivery, particularly in the thin myocardial tissue of the SVC. High-power ablation guided by LI and CF using the StablePoint catheter enables safe and effective SVCI with accurate real-time assessment of lesion quality.

In the presence of dual retrograde pathways, conventional Para-Hisian pacing may fail to reveal the slow pathway, likely due to masking by fast retrograde conduction. In such cases, Para-Hisian extra pacing-combining programmed right ventricular stimulation with differential His bundle capture-enables assessment of the slow retrograde conduction.

ABSTRACTBackground“A on V” tachycardia (AoV‐T) is classically considered suggestive of atrioventricular nodal reentrant tachycardia (AVNRT); emerging evidence suggests that other mechanisms may present with this electrogram pattern.ObjectiveTo reassess the prevalence and electrophysiologic characteristics of nonconventional mechanisms underlying AoV‐T.MethodsWe retrospectively reviewed 1484 consecutive electrophysiologic studies for narrow‐QRS tachycardia with His–atrial interval ≤ 70 ms at 10 centers (2015–2024). Diagnoses were adjudicated using atrial overdrive pacing (AOP), ventricular overdrive pacing (VOP), and His‐synchronized premature ventricular contractions (PVCs).ResultsMechanisms other than conventional AVNRT were identified in 24 patients (1.6%): atrial tachycardia (AT, n = 7), junctional tachycardia (JT, n = 6), orthodromic reciprocating tachycardia via an NV pathway (NV‐ORT, n = 6) or an NF pathway (NF‐ORT, n = 1), and AVNRT with a bystander NV pathway (n = 4). AT arose from the crista terminalis (n = 4) or para‐Hisian region (n = 3) and was diagnosed by V‐A‐A‐V response following VOP and/or absence of VA linking during differential AOP; dual AV nodal physiology was frequently observed. JT was diagnosed with atrial extrastimulus and/or A‐H‐H‐A response after AOP. NV/NF‐ORT was diagnosed by combined findings, including tachycardia reset/termination with His‐refractory PVCs, short PPI – TCL, orthodromic His capture, and V‐V‐A response following VOP; QRS fusion favored NV‐ORT. AVNRT with a bystander NV pathway was distinguished from NV‐ORT by pacing responses consistent with AVNRT despite evidence of NV conduction.ConclusionAlthough AVNRT predominates in AoV‐T, a small subset of cases reflects AT, JT, NV/NF‐ORT, or AVNRT with a bystander NV pathway. Comprehensive pacing maneuvers are essential to avoid misclassification.

The clinical relevance of patient disease awareness on risk factor control and clinical outcomes after atrial fibrillation (AF) ablation remains incompletely understood. We conducted a prospective cohort study enrolling 133 patients undergoing an initial AF ablation. Disease awareness was assessed using the Jessa Atrial Fibrillation Knowledge Questionnaire (JAKQ) -a 16-item instrument comprising 8 questions on general AF knowledge and 8 questions on oral anticoagulant therapy-administered before and 1 year after ablation. We divided them into the poor disease awareness group and good disease awareness group according to the median value (75%) of the JAKQ score about AF in general and compared the baseline patient characteristics and the 1-year changes in the JAKQ score, blood pressure, laboratory data, echocardiographic parameters, and AF/atrial tachycardia (AT) recurrence rate between the groups. Forty-two (31.6%) patients were classified as having a poor disease awareness (< 75% of the JAKQ score about AF in general), which was associated with hypertension, diabetes, dyslipidemia, and greater left atrial volume (LAV). These trends in the poor disease awareness group remained unchanged 1 year after the ablation. During the 25.3 [15.7-34.9] month follow-up, the AF/AT recurrence rate was significantly higher in the poor disease awareness than good disease awareness group (23.8% vs. 7.7%; p = 0.003 by the log-rank test). Poor disease awareness was linked to lifestyle-related diseases, greater LAV before and even 1 year after the ablation, making it a potential surrogate marker for AF/AT recurrence. These findings highlight the clinical significance of disease awareness for AF.

ABSTRACT Introduction Most of the existing algorithms for manifest accessory pathway (AP) localization fall short in the diagnostic accuracy of distinguishing different pathway locations, particularly in the septal region. Objective and Methods This study aims at testing an ECG criterion, the PR/QRS ratio for differentiating manifest right septal APs from the right free wall APs. PR interval, QRS width and PR/QRS ratio were measured in the most pre‐excited lead. AP location was determined in LAO 45°. Septal locations: from 12 to 6 O'clock including right anterior at 12 O'clock, right anteroseptal between 12 and 3 O'clock, right mid‐septal at 3 O'clock, right posteroseptal between 3 and 6 O'clock and right posterior at 6 O'clock. Free wall locations: extending between 6 and 12 O'clock including right posterolateral between 6 and 9 O'clock, right lateral at 9 O'clock and right anterolateral between 9 and 12 O'clock. Results Among 89 patients, a higher 100*PR/QRS ratio was observed in the septal wall group when compared to the free wall APs group (77.86 +/− 0.91 vs. 64.95 +/− 2.07 &lt; 0.001). Compared to PR interval and QRS duration, PR/QRS ratio had the best predictive performance with the highest accuracy (88.8%) and the largest area under the ROC curve (0.878) with a sensitivity of 93.8%, specificity of 75% and PPV of 91%. Conclusion The PR/QRS ratio is a simple yet powerful tool in localizing right sided accessory pathways that can potentially improve preprocedural counseling. However, this single‐center derivation study should be considered hypothesis‐generating and requires external validation.

Deep learning (DL) models have shown high accuracy in detecting reduced left ventricular ejection fraction (LVEF) from electrocardiograms (ECGs). However, their complexity limits clinical use. To address this, we aimed to develop and validate simplified machine learning (ML) models using numerical parameters from 12-lead ECGs to detect LVEF < 40% and to implement them in a user-friendly web application. We retrospectively analyzed ECG and transthoracic echocardiography data from 21 471 patients across two institutions. The dataset was divided into a development cohort (non-atrial fibrillation [non-AF]: n = 12 922; AF: n = 1281) and an external validation cohort (non-AF: n = 6284; AF: n = 984). Four machine learning algorithms-random forest (RF), extreme gradient boosting (XGBoost), support vector machine, and generalized additive models with LASSO-were evaluated for predicting LVEF as a continuous variable and binary outcome (< 40%). For continuous LVEF prediction, RF achieved R 2 values of 0.68 (non-AF) and 0.74 (AF) in internal validation but performed poorly in external validation. Other models showed R 2 values below 0.40 in internal validation. For binary classification, all models achieved area under the curve (AUC) values > 0.90 in the non-AF group during internal validation. RF and XGBoost showed strong performance in the AF group (AUC > 0.90 internally) and adequate accuracy externally (AUCs of 0.80-0.81 in AF and 0.90 in non-AF). We developed a simple web-based tool for preliminary screening of reduced LVEF using 12-lead ECG parameters.

Prolonged QT interval is common in end-stage renal disease (ESRD) on dialysis, but its long-term cardiovascular (CV) implications remain unclear. Using TriNetX network (2010-2024), we identified adults with ESRD on dialysis and categorized them by QTc status. After 1:1 propensity score matching (n = 3428/group), outcomes (hazard ratio [HR]) were assessed using Cox regression. Prolonged QTc (> 500 ms) was associated with higher risk of all-cause mortality (HR 1.67; p < 0.001), MACEs (HR 1.40; p < 0.001), cardiac arrest (HR 1.75; p < 0.001), sustained ventricular arrhythmia (HR 1.66; p < 0.001), new-onset atrial fibrillation (HR 1.12; p = 0.01), and acute myocardial infarction (HR 2.19; p < 0.001). In ESRD patients on dialysis, prolonged QT interval was independently associated with adverse CV outcomes and mortality.

COVID-19 infection can cause significant long-term health problems for patients. While there is no universally accepted definition for long COVID, it is usually identified by persistent symptoms that extend past 4 weeks after the initial SARS-CoV-2 infection with no other explanation. The cardiovascular system is one of the most important systems involved in long COVID, and even asymptomatic patients have evidence of cardiovascular injury after COVID-19. This study aims to determine the long-term risk of developing cardiac arrhythmias after SARS-CoV-2 infection. A comprehensive systematic search on Scopus, PubMed, Science Direct, and Web of Science databases was performed on August 24th, 2025. Cohort articles consisting of a healthy control group with no history of COVID-19 infection and individuals who recovered from COVID-19 for at least 30 days were included. Hazard Ratio (HR) and 95% confidence intervals (CI) were estimated using random-effect models. Fourteen studies were eligible for the meta-analysis. The overall arrhythmia risk was higher in patients with long COVID (HR: 1.74, 95% CI [1.39, 2.10], I 2 = 99.65%). Specific arrhythmias examined included atrial fibrillation (HR: 1.49, 95% CI [1.24, 1.73], I 2 = 98.57%), sinus tachycardia (HR: 1.69, 95% CI [1.21, 2.18], I 2 = 99.51%), sinus bradycardia (HR: 1.58, 95% CI [1.50, 1.66], I 2 = 65.80%), and ventricular arrhythmias (HR: 1.72, 95% CI [1.48, 1.95], I 2 = 96.89%). Patients with a more severe initial infection were at a higher risk of developing arrhythmias. The risk of developing cardiac arrhythmias is increased after COVID-19 infection in the long term.

ABSTRACTBackground and AimsEsophageal injury (EI) is a potentially serious complication of catheter ablation (CA) for atrial fibrillation (AF). However, data on its incidence and risk factors, particularly after radiofrequency catheter ablation (RFCA) and cryoballoon ablation (CBA), remain limited. This study aimed to identify predictors of EI in patients undergoing RFCA and CBA.MethodsIn this retrospective study, patients with AF who underwent de novo RFCA or CBA between December 2019 and April 2022 were evaluated. All underwent EGD within 2 days post‐ablation. EI severity was graded, and clinical predictors were analyzed using multivariate logistic regression.ResultsAmong 584 patients (mean age 62.8 ± 11.2 years, 68.6% male), 30 (5.1%) developed EI (RFCA: 5.0%, CBA: 6.3%). Most injuries were mild (Class I), and all resolved with proton pump inhibitor therapy. Compared with those without EI, affected patients had significantly lower body mass index (BMI) (24.5 ± 3.9 vs. 25.9 ± 3.4 kg/m2, p = 0.030) and reduced ejection fraction (EF) (48.9% ± 8.7% vs. 52.8% ± 6.8%, p = 0.023). Multivariate analysis identified BMI ≤ 24 kg/m2 (odds ratio [OR], 3.67; 95% confidence interval [CI], 1.69–7.96) and EF ≤ 40% (OR, 4.08; 95% CI, 1.54–11.56) as independent risk factors.ConclusionsEsophageal injury after catheter ablation for atrial fibrillation is not rare, but usually mild. Lower BMI and reduced LVEF were independent risk factors, regardless of ablation type. These results support selective endoscopic screening in high‐risk patients to enable early detection and prevent severe complications.