ABSTRACT Accurate identification of P waves on electrocardiogram (ECG) is essential in supraventricular tachycardias because U waves may resemble retrograde P waves, producing a pseudo–long RP interval and hiding typical atrioventricular nodal reentrant tachycardia (AVNRT). A 40‐year‐old woman presented with regular narrow‐complex tachycardia with a positive deflection immediately following the T wave, creating the impression of a long RP tachycardia. The electrophysiological study revealed a short VA interval with an H‐A‐V activation sequence, characteristic of typical slow‐fast AVNRT. This case emphasizes the diagnostic challenge posed by U waves at higher heart rates, which can obscure the true arrhythmia mechanism.

Background Conduction system pacing (CSP), including His bundle pacing and left bundle branch pacing, has emerged as a physiological alternative to right ventricular pacing (RVP) for patients developing conduction disturbances after transcatheter aortic valve replacement. Objective We performed a systematic review and meta-analysis to compare CSP with RVP. Methods PubMed, Embase, and Cochrane databases were searched according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A random-effects model was used for all outcomes, and heterogeneity was assessed using I2 statistics. The protocol was registered in PROSPERO (CRD420251125169). Results 8 studies, including 784 patients, were analyzed. At 15-month follow-up, all-cause mortality did not differ significantly between CSP (left bundle branch pacing in 74%) and RVP (odds ratio 0.76; 95% confidence interval [CI] 0.51–1.14; P = .15; I2 = 0%). CSP was associated with a shorter paced QRS duration after implant (mean difference −34.6 ms; 95% CI −40.2 to −29.1; P < .001) and higher left ventricular ejection fraction (mean difference +5.4%; 95% CI 3.5–7.3; P = .003) at 15-month follow-up. Heart failure hospitalization at 15 months was associated with a reduction in CSP (odds ratio 0.44; 95% CI 0.27–0.72; P = .006), whereas cardiovascular mortality, sensing, impedance, and lead dislodgement were similar between pacing strategies. Conclusion These findings suggest that CSP provides more physiological ventricular activation and may improve functional outcomes after transcatheter aortic valve replacement without affecting overall survival. Further randomized studies are warranted to confirm these observations.

Cardiac magnetic resonance (CMR) may provide insights into arrhythmogenic substrate in patients undergoing ventricular tachycardia (VT) ablation, but its prognostic value remains uncertain. We performed a systematic review and meta-analysis, following PRISMA guidelines, of available studies comparing CMR-derived parameters in patients with and without VT recurrence after ablation, from inception to March 2026. Primary outcomes included functional parameters - left ventricular ejection fraction (LVEF) and left ventricular (LV) mass, while secondary outcomes included ventricular volumes and late gadolinium enhancement (LGE) derived structural characteristics. Random-effects models were applied. Seven studies including 415 patients were analyzed, with 36.1

Background: When conservative therapies are insufficient for vasovagal syncope (VVS), procedural options such as permanent pacemakers or catheter ablation of ganglionated plexi (GP) may be considered. This meta-analysis aimed to evaluate the efficacy of GP catheter ablation in patients with VVS. Methods: A comprehensive literature search was performed in PubMed, Embase, and the Cochrane Library from 15 March 2024 to 10 May 2025. After duplicate removal, two reviewers independently screened studies and assessed full texts based on predefined criteria. A single-arm proportion meta-analysis was conducted. Results: Thirty-seven studies comprising 1585 participants were included. The pooled proportion of VVS recurrence after ablation was 8.9% (95% CI, 6.4–11.4%), but with substantial heterogeneity (I2 = 74.4%, p < 0.001). Sensitivity and subgroup analyses confirmed the robustness of the pooled estimate. A meta-regression was performed to further explore potential effect modifiers, but no covariate reached statistical significance. Conclusions: This meta-analysis suggests that ganglionated plexi catheter ablation may be associated with a reduced recurrence of vasovagal syncope in selected populations. However, the findings are based predominantly on non-randomized observational studies, and the high between-study heterogeneity limits the strength of inference. Future randomized controlled trials with standardized methodologies are needed to confirm the long-term efficacy and safety of this intervention.

Background: Patients with end-stage renal disease (ESRD) are at elevated risk for device-related complications following pacemaker implantation. Leadless pacemakers (LPMs) offer theoretical advantages over transvenous pacemakers (TVPs), but their safety and efficacy in this high-risk population remain unclear. Our aim was to compare clinical outcomes and complication profiles between leadless and transvenous pacemakers in patients with ESRD. Methods: We conducted a systematic review and meta-analysis according to PRISMA guidelines, including three retrospective studies comparing LPMs and TVPs in ESRD patients. The primary endpoint was overall complications post-implantation. Secondary outcomes included early mortality (within 30 days), access site complications, device-related events, thrombotic events, and respiratory complications. A random-effects model was used to pool odds ratios (ORs) and 95% confidence intervals (CIs). Results: Three studies comprising 10.075 ESRD patients were included. No significant difference was found in overall complications (OR 1.35, 95% CI 0.78–2.33, p = 0.14) or early mortality (OR 1.01, 95% CI 0.42–2.43, p = 0.97) between LPM and TVP groups. However, LPMs were associated with increased access site complications (OR 2.51, 95% CI 1.06–5.90, p = 0.04), thrombotic events (OR 1.42, 95% CI 1.14–1.78, p = 0.03), and respiratory complications (OR 1.43, 95% CI 1.01–2.03, p = 0.05). Device-related complication rates were similar (OR, 1.09; 95% CI, 0.63–1.88; p = 0.30). Heterogeneity was low across most outcomes. Conclusions: Among patients with ESRD, leadless pacemakers did not reduce overall complications or short-term mortality compared to transvenous systems and were associated with increased risk of certain procedural complications. These findings could support a personalized approach to device selection in ESRD and highlight the need for further prospective studies to guide clinical decision-making in this population.

Abstract Introduction The safety and effectiveness of electroporation/point by point pulsed field ablation (PP PFA) as emerging technoloy for catheter ablation (CA) of ventricular arrhythmias (VAs) has been described till now only in case reports. Purpose The aim of this observational retrospective study is to present real life data concerning the overall performance of PP PFA for CA of recurrent VA. Methods A total number of 13 consecutive patients (11 VTs and 2 PVCs), in whom recurrent VTs after RF ablation documented, were included. In all patients the substrate location was documented beforehand based on cardiac MRI or CT with myocardial thinning. For substrate mapping a high resolution multipoint mapping catheter was used. A complete success was defined as non inducibility of any arrhythmia at the end of procedure respectively lack of VA recurrence at follow – up. Results Excepting 2 patients, all other had a non ischemic cardiomyopathy as underlying heart disease (mean age 63 ± 8 y/o, mean LVEF 42 % ± 9 %). In every patient at least one conventional RF CA has been performed previously (mean 2 ± 1) and 38 % of patients had a previous epicardial RF VT ablation. The PP PFA VT ablation was performed endocardialy in 11 patients (84 %), respectively epicardialy in 2 patients. The ablation sites had a septal location in 53 % of patients and other localisation in 47 % of patients. The applied energy was 25 A. The overall acute complete success was achieved in 77 % patients. At medium 6 ± 3 months follow up a complete success was present in 46 % cases. Most frequently a VT recurrence after PP PFA ablation was encountered in patients with combined septal and nonseptal substrate distrubution. After PP PFA, the RF CA strategy due to recurrent VAs was endocardial in 2 patients, respectively epicardial 2 in cases and bipolar in 1 case. No PP PFA redos were undergone. Three major complications have been documented (1 tamponade, 1 AV block III° and 1 complete LBBB). Conclusion As bailout strategy in patients with failed conventional CA, PP PFA represents a safe strategy. Specific complications like temporary atrioventricular or intraventricular conduction disturbancies are extremely rare, reversible but not life threathening. The midterm success is satisfactory but still limited in patients with intramural substrate.

Long QT syndrome (LQT) and WPW syndrome are causes of sudden cardiac death (SCD) in the young, and their association has been rarely reported. A 26-year-old woman presented with recurrent syncope. Her ECG showed a short PR interval, wide QRS (150 ms) due to a delta wave, and QT prolongation (QT 580 ms, QTc 648 ms). ECG monitoring documented recurrent salvos of a self-terminating wide QRS tachycardia, generally slightly polymorphic, sometimes with “torsade des pointes” (TdP) appearance, which were linked to the syncopal/presyncope episodes. Electrophysiologic monitoring diagnosed a right para-hisian accessory pathway with a very short ERP (240 ms baseline, <200 ms after isoproterenol). The pathway was ablated successfully. Despite QRS narrowing (80 ms), QT prolongation persisted after ablation (QT 620 ms, QTc 654 ms), with short runs of TdP, despite beta-blocker treatment, which was increased to the maximal dosage. A dual-chamber implantable cardioverter defibrillator (ICD) was implanted. To our knowledge, this is the first case report of an association between LQT and WPW syndrome in which both conditions are associated with an increased risk of SCD.

BACKGROUND:Prediction of cardiac resynchronization therapy (CRT) response, particularly a super-response, is of great importance.STUDY QUESTION:The aim of our study was to assess the predictors for super-responders in CRT.STUDY DESIGN:We conducted a retrospective, observational study, which finally included 622 patients with heart failure treated with CRT between January 2008 and May 2020 who had a minimal follow-up of 6 months after CRT.MEASURES AND OUTCOMES:A total of 192 super-responders, defined by a left ventricular ejection fraction (LVEF) of at least 45%, and/or minimum 15% increase in LVEF and an improvement of the New York Heart Association functional class by at least 2 degrees at the last follow-up, and the rest of 430 patients who did not fulfill the super-responder criteria.RESULTS:The highest rate of super-responders (41.91%, n = 171) was at patients with left ventricle-only pacing with optimal fusion (OPT) compared with patients with biventricular (BiV) pacing (9.81%, n = 21, P < 0.000). In the OPT group, univariable analysis showed that nonischemic cardiomyopathy, a smaller degree of mitral regurgitation, and better left ventricle function at enrollment were predictors for super-response compared with the BiV group where a narrower QRS after implantation, nonischemic cardiomyopathy, and a better baseline LVEF were predictors for super-responders. In the multivariable analysis, both narrower QRS after implantation and nonischemic cardiomyopathy were independent predictors for super-response in the BiV group compared with OPT where nonischemic cardiomyopathy remained the only independent predictor for super-response.CONCLUSIONS:In this retrospective study, OPT CRT programing was an additional predictor of super-response to CRT besides nonischemic cardiomyopathy.

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Catheter ablation of VTs and intramyocardial substrate (IS) remains a challenge that may require alternative mapping and ablation strategies such as bipolar ablation (BA) to achieve VT non inducibility. However, the long-term success of these alternative strategies is still uncertain. Purpose The aim of this study was to report the midterm center experience success of BA RF ablation of VT in patients with documented intramyocardial scar in cardiac imaging. Methods 19 patients with documented intramyocardial substrate on cardiac imaging (cardiac MRI or cardio CT with delayed enhancement) and VT recurrences after at least one conventional catheter ablation were retrospectively included. The intraprocedural success (i.e. VT non inducibility at the end of procedure) respectively midterm success (i.e VT recurrence after 6 months from BA) were investigated. The ablation was performed using a special RF generator which permits bipolar RF ablation between 2 irrigated catheters. Results A total number of 19 patients were included (100 % men, mean age 66,7 ± 9,16 y/o). The mean LVEF was 39,5 ± 5,7. The distribution of underlying structural heart disease was as follow: 21 % ischemic cardiomyopathy (4 out of 19 patients), 52 % dilative cardiomyopathy (10 out of 19 patients) respectively 26 % other etiologies (5 out of 19 patients). A mean number of 2 ± 1 conventional VT ablation were previously performed. In almost all patients (94 %, 18 out of 19 patients) the clinical VT was induced before the BA (mean CL 342 ± 91ms). The BA was performed predominantly septal (84%, 16 out of 19 patients). In 3 patients an endo/epicardial BA was performed. No VT was inducible any more at the end of procedure in 15 patients (79 %). At a mean follow up of 1 ± 0,5 years no recurrence of clinical VT was noted but non-clinical VT recurrence was seen in 9 patients (47 %) exclusively in patients with septal substrate. Conclusion BA represents a good alternative strategy for CA in patients with IS and failed conventional VT ablation with good acute success but high VT recurrence rate in patients with septal IS. Intramural LGE on lateral LV wall Epi/endocardial ablation catheters

Indications for cardiac implantable electronic devices (CIEDs) are increasing. Almost one-third of device-related infections are endocarditis. Transvenous lead extraction (TLE) has emerged as an effective and safe approach for treating device-related infections and complications. Multiple types of extraction tools are being used worldwide. Our goal is to evaluate the safety and effectiveness of TLE using non-powered extraction tools. The study included patients between October 2018 and July 2022 requiring TLE according to EHRA expert consensus recommendations on lead extraction. A total of 88 consecutive patients were included. Indications for TLE included device-related infections in 74% of the patients. Of those, 32% had device-related endocarditis with or without sepsis. Staphylococcus Aureus was the most frequent pathogen in patients with endocarditis and positive bacteremia, and 57% had negative bloodstream cultures. A total of 150 cardiac pacing and defibrillator leads were targeted for extraction. The mean dwell time for leads was 6.92 ± 4.4 years; 52.8% were older than 5 years, 15.8% were older than ten years, and the longest lead dwell time was 26 years. Patients’ age varied between 18 and 98, with a mean age of 66 ± 16 years. Sixty-seven percent of patients were males. Using only non-powered extraction tools, we report 93.3% complete lead removal and 99% clinical success with partial extraction. We report no procedure-related death nor major complications. Minor complication incidence was 6.8%, and all complications resolved spontaneously. The 30-day mortality rate was 3.4%. TLE using non-powered extraction tools is safe and effective even without surgical backup on site.

Atrial septal defect (ASD) represents the most common congenital heart defect identified in adulthood. Atrial and ventricular geometric remodeling due to intracardiac shunt increase the risk of arrhythmias, especially atrial fibrillation (AF). Clinical, echocardiography, electrocardiogram, and device-related predictors may be used to assess the risk of atrial arrhythmias after ASD closure. The underlying mechanisms in these patients are complex and at least in part independent of the structural remodeling secondary to hemodynamic overload. Device closure of the ASD itself and its timing impact future arrhythmia risk, as well as posing a challenge for when transseptal puncture is required. Sudden cardiac death (SCD) risk is higher than in the general population and an implantable cardioverter-defibrillator (ICD) may be indicated in selected cases.

Cardiac implantable electronic devices are now widely used worldwide and the numbers are increasing exponentially. Subsequently, long-term complications have increased. Transvenous lead-extraction (TLE) is the gold standard for removing infected devices, treating systemic device-related infections including endocarditis, and removing devices for other non-infectious complications. Most patients still require device therapy after TLE for several indications, including lifesaving defibrillation or pacing in pacemaker-dependent patients. The decision to reimplant is challenging, particularly when the primary cause for device removal includes device-related infections and patients frequently are pacemaker dependent. We aim to present our strategy for reimplanting after performing TLE in 88 consecutive patients. We performed transvenous removal of 150 pacemaker and defibrillator leads, of which 74% for local or systemic infection. We report a 99.3% clinical success after TLE. Out of 88 patients who had undergone TLE and after reanalysing the device indication, 67 patients (76%) still had indication for device removal, but three of them refused to undergo reimplant and 58 were re-implanted. Of the re-implanted patients, 58.6% were implanted on the contra-lateral side, 38% on the ipsilateral side and two patients who had been previously implanted with ICD were reimplanted with a subcutaneous implantable cardioverter defibrillator (S-ICD). Up to 34.4% of patients were re-implanted during the same TLE procedure, which was performed for device up-grade in patients with venous occlusion, 24% were implanted during the same hospital admission for TLE but not during TLE, and 41.3% were discharged and reimplanted afterwards. With this strategy for reimplantation, we report no re-infections and no device-removal-related arrhythmic major events or deaths during one-year follow-up. In conclusion, most patients still require device therapy after TLE. In patients with previous infection of the device, the reimplantation strategy should be carefully analyzed to prevent infection relapse and limit the consequences of the absence of the device.

Background and aimsThere is limited data concerning the effect of non-revascularized chronic total occlusions (NR-CTOs) after VT ablation. This study sought to evaluate the impact of NR-CTOs after ablation for electrical storm (ES).MethodsPost-hoc retrospective analysis of data regarding 64 consecutive post-myocardial infarction patients (out of which 12 patients with NR-CTOs and 52 without NR-CTOs) undergoing substrate ablation for ES with an available median follow-up of 37.53 (7.25–64.65) months. Ablation result was assessed by inducibility of sustained monomorphic VT (SMVT) during final programmed ventricular stimulation (PVS). The primary endpoints were all-cause mortality and VT/VF recurrences after ablation, respectively, stratified by the presence of NR-CTOs. The secondary endpoint was to assess the predictive effect of NR-CTOs on all-cause mortality and VT/VF recurrences in relation to other relevant prognostic factors.ResultsAt baseline, the presence of NR-CTOs was associated with higher bipolar BZ-to-total scar ratio (72.4% ± 17.9% vs. 52% ± 37.7%, p = 0.022) and more failure to eliminate the clinical VT (25% (3) vs. 0% (0), p < 0.001). During follow-up, overall all-cause mortality and recurrences were more frequent in the NR-CTO subgroup (75% (9) vs. 19.2% (10), log rank p = 0.003 and 58.3% vs. 23.1% (12), log rank p = 0.042 respectively). After adjusting for end-procedural residual SMVT inducibility, NR-CTOs predicted death during follow-up (HR 3.380, p = 0.009) however not recurrence (HR 1.986, p = 0.154).ConclusionsNR-CTO patients treated by RFCA for drug-refractory ES demonstrated a higher ratio of BZ-to-total-scar area. In this analysis, NR-CTO was associated with worse acute procedural results and may as well impact long-term outcomes which should be further assessed in larger patient populations.

Ventricular arrhythmias (VAs) are frequent in hypertensive patients, and this association may have clinical significance. There are multiple responsible mechanisms: left ventricular hypertrophy (LVH), renin–angiotensin–aldosterone system and sympathetic nervous system activation, and the presence of atrial fibrillation (AF), genetic factors, heart failure (HF), QT interval (QTc) prolongation, myocardial ischemia, delayed or early afterdepolarizations, and electrolyte imbalances. Pharmacological treatment in association with lifestyle changes are aimed at prevention or regression of LVH with blood pressure (BP) control. Other therapeutic options according to the severity of the ventricular arrhythmia include implantable cardioverter defibrillator, ablation, renal sympathetic denervation, and cardiac sympathetic denervation (CSD).

INTRODUCTION:We report the case of a 41-year-old female with documented narrow QRS tachycardia. During electrophysiological study, both orthodromic and antidromic atrioventricular reentry tachycardia (AVRT) were demonstrated as well as short episodes of pre-excited atrial fibrillation. Programmed atrial stimulation resulted in decremental anterograde conduction on the AP, thus confirming an unexpected Mahaim accessory pathway (AP) diagnosis.DISCUSSION:Limited 3D activation maps of the right atrium during orthoAVRT, respectively, and the right ventricle (RV) during antiAVRT were constructed and helped accurately describe the atrial and ventricular insertion points, which were superposed on the tricuspid ring, confirming the existence of a single short atrio-ventricular right free wall AP. Short atrioventricular APs with anterograde Mahaim-type conduction concomitantly sustaining orthodromic AVRT are extremely rare.CONCLUSIONS:Electroanatomical 3D mapping may help both to clarify the diagnosis and increase the success rate by accurately describing the insertion points of complex accessory pathways.

Zusammenfassung Ein elektrischer Sturm ist definiert als rezidivierende ventrikuläre Tachykardien innerhalb von 24 Stunden und ist assoziiert mit einer schlechten kurz- und langfristigen Prognose. In der Regel ist neben initiierenden Auslösern in der Vielzahl der Fälle ein arrhythmogenes Substrat vorhanden. Durch die zunehmende Anzahl an Patienten mit implantierten Defibrillatoren steigt auch die Zahl der Patienten, die sich akut entweder im niedergelassenen, aber auch im stationären Sektor vorstellen. Dies ist im Wesentlichen abhängig von den individuellen Beschwerden, die von asymptomatisch bis zur Reanimationssituation reichen können. Ein standardisiertes Vorgehen fokussiert auf Auslöser der Arrhythmie, die darunterliegende strukturelle Herzerkrankung und den hämodynamischen Status. Das akute Management beinhaltet normalerweise eine multimodale Medikation sowie leichte bis moderate Sedierung. Die Katheterablation spielt eine dezidierte Rolle in der Anfangsphase der Behandlung und weniger in der Akutphase des elektrischen Sturmes.

Ventricular arrhythmias (VA) are a major cause of sudden cardiac death (SCD). Echocardiography is the first widely available imaging tool which guides VA management strategies. Along with other invasive and noninvasive imaging techniques, it provides essential information for identification of VA substrate such as differentiation between ischemic and non-ischemic etiology and identification of structural heart disease. Both classic as well as novel echocardiographic techniques such as left ventricular strain measurement and mechanical dispersion assessment provide prognostic information and assist in risk stratification. Furthermore, intracardiac echocardiography may have an adjunctive role for the VA ablation by providing real-time visualization of cardiac structures, continuous monitoring of catheter location and early recognition of procedural complications. This review gathers all relevant information that echocardiography may offer prior to VA ablation procedures.

Cardiac resynchronization therapy (CRT) is a well proven treatment for heart failure patients with reduced ejection fraction (HFrEF). There is a strong need to find new factors that predict and/or influence the response to CRT. Most previous studies have focused mainly on the left ventricle (LV). The role of the right ventricle (RV) in CRT patients is uncertain.

To investigate how mechanical loading stimulates bone cells, we subjected murine osteoblast-like cells, MC3T3E1, to fluid flow generated by shaking culture dishes. Since we had previously found that egr-1 mRNA is up-regulated by the flow, and that the regulation involves tyrosine kinase, we examined which proteins are tyrosine-phosphorylated by flow. Western blotting and immunoprecipitation of cell lysates showed tyrosine phosphorylation enhancement of many proteins, including ERK2 and Shc, and activation of ERK1/2. Although these responses did not occur in serum-free media, addition of EGF or bFGF recovered the responses. AG1478, an inhibitor of EGF receptor kinase activity, abolished tyrosine phosphorylation enhancement, ERK1/2 activation, and egr-1 mRNA accumulation induced by the flow of EGF-containing serum-free media. These results suggest that growth factor signaling pathways are involved in these responses. Repetition of fluid flow induced repeatedly up-regulation of egr-1 mRNA. Such events may also occur in bone under mechanical loading.