BACKGROUND:Idiopathic outflow tract premature ventricular contractions (PVCs) are most commonly localized in the right ventricular outflow tract (RVOT). The clinical significance of sustained outflow tract ventricular tachycardia (OT-VT) regarding any predominance to one specific anatomic area remains uncertain. SUBJECTIVE:This study aimed to characterize the clinical and procedural features of patients with idiopathic sustained OT-VT and determine whether the site of origin can be predicted from clinical presentation. METHODS:This retrospective cohort included 35 consecutive patients with documented sustained OT-VT (≥ 30 s), from over 400 patients referred for idiopathic outflow tract arrhythmia ablation. Baseline clinical and echocardiographic characteristics were collected and procedural data reviewed. Sites of arrhythmia origin were identified by electroanatomic mapping and ablation outcomes. RESULTS:Sustained OT-VT arose exclusively from right-sided outflow tract foci, most commonly the postero- or anteroseptal RVOT (n = 26, 74.3% and n = 6, 17.1%, respectively) and less frequently from the posterolateral (n = 3, 8.6%). No cases of sustained VT from the LVOT were observed. Acute ablation success was achieved in all patients. During 12 months of follow-up, recurrence occurred in three patients (8.6%), all of whom were successfully managed with repeat ablation. No complications were observed. CONCLUSION:In patients with structurally normal hearts, sustained OT-VT in our cohort arose exclusively from the RVOT. Recognition of this pattern can guide mapping and ablation strategies.

BACKGROUND:While interventional strategies have expanded the options for long term rhythm restoration, rate control continues to play a pivotal role in the treatment of atrial arrhythmias; however, pharmacologic strategies alone often fail in achieving effective rate control. AIMS:To examine long-term outcomes in patients who have undergone atrioventricular node ablation (AVNA) for the management of symptomatic atrial arrhythmias. METHODS:This observational Study Assessed Patients Who Underwent AVNA For Rate Control of Atrial Fibrillation (AF) Or Atrial Tachycardia (AT) Between April 2014 and February 2022. Clinical data, along with follow-up information including cardiac device interrogation were analyzed. A composite safety endpoint, Encompassing Heart Failure (HF) Rehospitalization, lead revision, device infection, or upgrade for cardiac resynchronization therapy (CRT), was evaluated. Additionally, structured patient interviews were conducted to assess quality of life outcomes. RESULTS:192 patients (76 females (39.6%), mean age 73.7 ± 10 years) were included into the study. Patients suffered from paroxysmal AF in 10 cases (5.2%), persistent AF in 138 cases (71.9%) and AT in 44 cases (22.9%). Acute AVNA was successful in all patients. Two pseudoaneurysms at the femoral puncture site occurred as the only periprocedural complications. Mean follow-up duration was 907.0 ± 609.7 days. Persistent complete AV block was present in 191 patients (99.5%) during follow-up. The composite safety endpoint occurred in 58 (30.2%) patients. Quality of life significantly improved in most patients with a relevant regression in EHRA and NYHA scores. CONCLUSION:AVNA is effective and safe in an all-comer patient population with high success rates in terms of rate control, QOL improvement and a favorable safety profile during long-term observation.

BACKGROUND AND AIMS:Effective intraprocedural anticoagulation is essential during catheter ablation of atrial fibrillation (AF) and left atrial tachycardia (AT) procedures. This study evaluated a novel, standardized, nurse-led heparin protocol regarding anticoagulation performance and safety. METHODS:Consecutive patients undergoing AF or AT ablation between May 2022 and 2023 were treated using a standardized heparinization protocol managed by electrophysiology nursing staff (study group) and compared with consecutive patients undergoing ablation between May 2021 and April 2022, in whom heparin was administered at the operator's discretion (control group). Patients in the study cohort received an initial dose of 5000 IU heparin after venous access and a supplemental bolus (1000 IU/10 kg above 50 kg bodyweight) after transseptal puncture. ACT was then assessed every 20 min using a point-of-care coagulation device in both groups. Repeat heparin administration was autonomously performed by nurses in the study group following a standardized protocol. The primary endpoint was the proportion of patients in whom at least one intraprocedural ACT measurement exceeded 300 s at any time during the procedure. RESULTS:Each group included 655 patients with comparable baseline characteristics. The study group more frequently achieved the therapeutic target (ACT > 300 s, 84.6% vs. 59.7%, p < 0.0001), reached therapeutic ACT faster, and showed fewer exclusively subtherapeutic ACT values. Excessive anticoagulation was less common (ACT > 400 s: 2.0% in the study group vs. 5.0% in the control group, p = 0.0027). Complication rates were low and similar in both groups. CONCLUSIONS:A standardized, nurse-led heparinization protocol improved the speed, consistency, and precision of intraprocedural anticoagulation during left atrial ablation without increasing procedural complications.

BACKGROUND:The CASTLE-HTx trial (NCT04649801) showed that the combination of catheter ablation and guideline-directed medical therapy (GDMT) was associated with a lower likelihood of a composite of death from any cause, implantation of a left-ventricular assist device (LVAD), or heart transplantation (HTx) in patients with end-stage heart failure (HF) and atrial fibrillation (AF). AIMS:This is an ancillary analysis with the generalized pairwise comparison methodology of the main outcomes of CASTLE-HTx. METHODS:In CASTLE-HTX, 194 patients were randomized to catheter ablation and GDMT (n = 97) or medical therapy alone (n = 97). The first hierarchical outcome was a composite of (1) death from any cause, (2) urgent HTx, (3) implantation of an LVAD, and (4) frequency of hospitalizations for worsening HF. Secondary analysis also included AF burden and left-ventricular ejection fraction improvement. Treatment effects are reported as net treatment benefit (NTB) and win odds, with corresponding confidence intervals (CIs). RESULTS:Patients randomized to ablation had more wins with respect to death from any cause (28.4%/12.4%), HTx (4.3%/2.1%), LVAD implantation (4.2%/0.6%), and hospitalizations for worsening HF (24.8%/11.3%). 61.6% of pairs favoured ablation, 26.4% medical therapy, and 12.0% were tied. This resulted in a restricted NTB at 3 years of 35.3% (95% CI, 19.8-49.0, P < .001) favouring ablation (win odds: 2.09; 95% CI, 1.49-2.92). In the secondary analysis, 67.0% of pairs favoured ablation against 28.6% of pairs favouring medical therapy. The restricted NTB was 38.4% (95% CI, 22.8-52.0, P < .001) in favour of ablation (win odds: 2.25; 95% CI, 1.59-3.17). CONCLUSIONS:This pairwise analysis of CASTLE-HTx confirms the clinical benefits of early catheter ablation in addition to GDMT among AF patients in end-stage HF. The treatment benefit was primarily driven by mortality and HF hospitalizations.

Left bundle branch area pacing is being increasingly adopted in routine clinical practice as a more physiological alternative to right ventricular and biventricular pacing. Understanding the concepts of this pacing modality may be a hurdle for the non-electrophysiologist and specialists alike. This review article aims to explain in a didactic manner the anatomical and electrophysiological principles underlying left bundle branch area pacing.

BACKGROUND:In patients with structural heart disease (SHD) and moderately impaired left ventricular ejection fraction (LVEF > 35%), data on outcomes after ventricular tachycardia (VT) ablation remain limited. This analysis focuses on VT recurrence after ablation in patients presenting with sustained VT and LVEF > 35% within a secondary-prevention population. OBJECTIVE:To evaluate procedural outcomes and long-term VT recurrence after catheter ablation in SHD patients with LVEF > 35%. METHODS:We analyzed 219 consecutive patients with SHD and LVEF > 35% undergoing VT ablation, including 89 with ischemic cardiomyopathy (ICM) and 130 with non-ischemic cardiomyopathy (NICM). Procedural characteristics, complications, and VT recurrence during follow-up were compared between groups. RESULTS:ICM patients were older, more frequently hypertensive, and had slightly lower LVEF than NICM patients. Ablation was predominantly endocardial in ICM, whereas combined endocardial-epicardial ablation was required in 28% of NICM patients (p < 0.001). Acute VT non-inducibility was achieved more frequently in ICM than in NICM (93% vs 67%; p < 0.001). Procedural complications were infrequent and comparable between groups (6% overall; p = 0.342). During follow-up, VT recurred in 35% of patients, more frequently in NICM than ICM (42% vs 25%; p = 0.004). Cardiomyopathy type emerged as the only independent predictor of VT recurrence (HR 2.312, CI 1.3-4.0, p = 0.004), while acute non-inducibility was associated with a lower recurrence risk. CONCLUSION:VT ablation in SHD patients with LVEF > 35% was associated with acceptable safety and moderate arrhythmia control. Outcomes were more favorable in ICM than in NICM, reflecting the heterogeneity of arrhythmic risk in this secondary prevention population.

BACKGROUND:The CASTLE-HTx (Catheter Ablation for Atrial Fibrillation in patientS With End-sTage Heart Failure and Eligibility for Heart Transplantation; ClinicalTrials.gov identifier NCT04649801) trial showed that the combination of catheter ablation and guideline-directed medical therapy (GDMT) was associated with a lower likelihood of a composite of death from any cause, implantation of a left ventricular assist device, or heart transplantation (HTx) in patients with end-stage heart failure (HF) and atrial fibrillation (AF). OBJECTIVE:This analysis evaluates the cost-effectiveness of catheter ablation plus GDMT vs medical therapy alone in patients with end-stage HF and AF referred for HTx evaluation. METHODS:In CASTLE-HTx, we randomized 194 patients in end-stage HF and AF to receive catheter ablation and GDMT (n = 97) or medical therapy alone (n = 97). Details of study design, outcome definitions, and results have been published. A cohort-based Markov model projected lifetime costs, life-years (LYs), and quality-adjusted life-years (QALYs) from the perspective of the German statutory health insurance system using 3-year outcomes from CASTLE-HTx. RESULTS:In lifetime projections, the combination of AF ablation and GDMT was associated with a mean survival gain of ∼1.7 LYs per patient at an incremental cost of ∼€12,000, yielding an incremental cost-effectiveness ratio of ∼€7300 per LY gained. The incremental cost-effectiveness ratios per QALY in lifetime projections (€8600) and at 36 months (€30,400) were below €50,000 per QALY, indicating cost-effectiveness at contemporary thresholds. Within 36 months, this survival benefit resulted in a gain of 0.34 LYs, reflecting prevention of death and worsening HF. The long-term benefit emerged early and remained consistent across sensitivity analyses. CONCLUSION:The combination of catheter ablation and GDMT is cost-effective and economically favorable in patients with end-stage HF and AF who are referred for HTx evaluation.

Background Atrial fibrillation (AF) and functional mitral regurgitation (FMR) frequently coexist and are linked through shared mechanisms of atrial and ventricular remodeling. Both catheter ablation and transcatheter edge-to-edge mitral valve repair (M-TEER) improve clinical status, yet the optimal sequence of these interventions remains unclear. Objective This study evaluates real-world outcomes in patients with AF and FMR, comparing catheter ablation and M-TEER as initial strategies, with focus on MR severity, symptom stability, all-cause mortality, and all-cause cardiac hospitalizations. Methods We conducted a single-center retrospective analysis of patients with AF and moderate to moderate-to-severe FMR. Patients were grouped according to the initial treatment strategy: AF ablation or M-TEER. Clinical and echocardiographic data were reviewed at baseline and follow-up. A retrospective two-year follow-up was performed to evaluate changes in MR severity, symptom stability, all-cause mortality, and all-cause cardiac hospitalizations Results A total of 281 patients were included (129 M-TEER, 152 AF ablation). MR severity improved more frequently following M-TEER (p < 0.001). However, AF ablation was associated with better symptom stability (69% vs. 44%, p < 0.001), markedly lower all-cause mortality (3% vs. 14%, p= 0.002), less all-cause cardiac hospitalizations (p = 0. 0.019), and significant improvment in left ventricular ejection fraction at follow-up (53 ± 11.1%vs. 47 ± 13.9%, p < 0.001). Conclusion M-TEER was associated with greater MR reduction, while AF ablation was associated with more favorable clinical outcomes. These findings likely reflect stage-dependent management rather than treatment superiority and require confirmation in prospective studies.

BACKGROUND:Epicardial catheter ablation is an established treatment for ventricular tachycardia (VT) in patients with structural heart disease (SHD); however, VT recurrence remains frequent, particularly in advanced cardiomyopathy. OBJECTIVE:This study aimed to identify clinical and electrophysiological determinants of VT recurrence after epicardial VT ablation in SHD. METHODS:74 patients with SHD undergoing epicardial VT ablation were included. Acute procedural outcomes, VT recurrence, and adverse clinical events were assessed. RESULTS:Nonischemic cardiomyopathy was the predominant etiology. Epicardial scar predominantly involved basal-lateral left ventricular regions with periannular and outflow tract extension. Acute procedural noninducibility was achieved in 49 patients (66%), whereas VT recurrence occurred in 37 patients (50%) during follow-up of 17 months. In cause-specific Cox analysis, electrical storm (hazard ratio [HR] 3.130; 95% confidence interval [CI] 1.421-6.893; P = .005), longer VT cycle length (HR 2.835; 95% CI 1.211-6.638; P = .016), and higher body mass index (HR 2.918; 95% CI 1.365-6.236; P = .006) were independently associated with VT recurrence. During follow-up, 7 patients died, 10 underwent heart transplantation, and 2 required ventricular assist device implantation. CONCLUSION:Combined endocardial and epicardial VT ablation in advanced SHD was associated with moderate acute success, whereas VT recurrence remained common during follow-up. Electrical storm, longer VT cycle length, and higher body mass index were independently associated with an increased risk of recurrence.

Catheter ablation is an established therapy for ventricular tachycardia (VT); however, hemodynamic instability frequently limits procedural mapping and success. Temporary mechanical circulatory support (tMCS) devices are increasingly used to maintain end-organ perfusion during VT ablation, yet their impact on clinical outcomes remains uncertain. We aimed to evaluate the impact of tMCS on clinical outcomes and periprocedural complications in patients undergoing VT ablation. A systematic search of PubMed/MEDLINE, Scopus, Web of Science, and Cochrane CENTRAL was conducted from database inception through December 2025. We included observational studies enrolling adult patients undergoing VT ablation with tMCS, compared with VT ablation performed without MCS. Primary outcomes were all-cause mortality, in-hospital mortality, procedural success, VT recurrence, and major adverse cardiovascular events (MACE). Ten observational studies comprising 16,838 patients were included, of whom 1402 received tMCS. There was no significant difference in all-cause mortality between tMCS and no-MCS groups (RR 1.71, 95% CI 0.68 to 4.26), procedural success (RR 1.05, 95% CI 0.92 to 1.21), VT recurrence (RR 0.99, 95% CI 0.80 to 1.22), or MACE (RR = 0.79, 95% CI: 0.62 to 1.01). However, tMCS use was associated with significantly higher in-hospital mortality (RR 7.41, 95% CI 4.77 to 11.66). The tMCS group also demonstrated increased risks of stroke, pericardial effusion or tamponade, and periprocedural complications. In non-randomized studies, tMCS during VT ablation was not associated with improved long-term outcomes, while higher in-hospital mortality and complications likely reflected patient selection and timing of support rather than adverse device effects.

Electrical storm (ES) is associated with high mortality and may lead to worsening of heart failure or repeat ICD therapy deliveries. Catheter ablation of ventricular tachycardia (VT) in ischemic heart disease has proven to be successful in reducing ventricular arrhythmia recurrences. The prognostic impact of ablation on patients with ES needs to be further elucidated. To analyse the impact of catheter ablation on prognostic outcomes in patients with electrical storm. A composite study endpoint consisting of all-cause death, implantation of a left ventricular assist device or heart transplantation was in consecutive patients who were admitted for ES therapy to our intensive-care unit from 2016 to 2022. Patients who underwent ablation were compared with propensity score-matched patients who underwent conservative treatment. Propensity-score matching of 155 patients with ES resulted in 51 patients undergoing catheter ablation and 51 patients with conservative therapy only with comparable baseline characteristics. A study endpoint event occurred in 18 patients (35

The coronary sinus and its tributaries constitute the anatomical foundation for successful cardiac resynchronization therapy. Despite the emergence of conduction system pacing as a physiological alternative, conventional transvenous CRT retains its important role—not all clinical scenarios can be addressed by left bundle branch area or His bundle pacing alone. Understanding coronary venous anatomy therefore remains essential for every implanting physician. This review provides a clinically oriented analysis of coronary venous anatomy as it pertains to left ventricular lead implantation.We examine the embryological origins of the coronary sinus, explaining why variants such as persistent left superior vena cava and obstructive Thebesian and Vieussens valves occur. The gross anatomy section details coronary sinus dimensions, ostial localization, and tributary classification using attitudinally correct nomenclature. Microanatomical considerations include wall thickness gradients, subepicardial adipose tissue thickness, and myocardial sleeve distribution.We review imaging modalities—fluoroscopy, computed tomography, and magnetic resonance imaging—emphasizing their complementary roles in preprocedural planning and real-time guidance. Catheter and wire handling techniques are discussed, from cannulation strategies to lead delivery. Electrophysiological parameters including Q-LV and S-QRS intervals are examined in the context of anatomical lead positioning.Finally, we analyze how anatomy influences outcomes, complications, and non-response. Understanding the coronary venous system transforms cardiac resynchronization therapy from a technical procedure into an anatomically informed intervention where success depends on matching therapeutic goals with individual patient anatomy.

This clinical consensus document proposes standardized atrial segments for 3D imaging, electroanatomical mapping and computational modelling, based on anatomical, electrophysiological and clinical considerations, with precise definitions of regional borders allowing for reproducible and automated regionalization. 3D imaging and high-resolution electroanatomical mapping have become an integral part of cardiac electrophysiology and the management of patients with arrhythmias. However, to perform regional quantitative analyses and intra- and inter-individual, as well as cross-modality comparisons, a universal definition of atrial regions and their boundaries is required. While for the left ventricle there is already an established standardized regionalization (AHA 17-segment model), there is no such consensus for the atria. In a multi-disciplinary writing group consisting of cardiologists, cardiac electrophysiologists, cardiovascular imaging specialists, and anatomists as well as specialists in computational cardiac modelling from European Heart Rhythm Association and European Association of Cardiovascular Imaging, a standardized regionalization based on a 15-segment bi-atrial model was elaborated. This clinical consensus document will enable consistent regional analyses and homogeneous data acquisition across different centres and modalities, and may thus have a significant impact on atrial arrhythmia research and personalized treatment approaches based on individual arrhythmia patterns and phenotypes.

Background Transseptal puncture (TSP) is critical for atrial fibrillation (AF) ablation. However, patients with atrial septal occluders (ASOs) for atrial septal defects (ASDs) or persistent foramen ovale (PFO) pose unique challenges. Objective This study aimed to evaluate the peri- and postprocedural safety, AF recurrence, and incidence of newly developed ASD/PFO up to 12 months postprocedure. Methods This multicenter, prospective observational study included 59 patients (mean age 61.2 ± 12.1 years, 56% male) with drug-refractory AF who underwent pulmonary vein isolation (PVI) between 2019 and 2024. Of these patients, 38 had ASDs and 21 had PFOs, with ASOs in situ. All punctures (single TSP) were performed under fluoroscopic guidance. Results The majority of TSP positions in the interatrial septum related to the ASO was inferior-posterior to the ASO (66.1%) or inferior-anterior (23.7%). In case of failure of the inferior part, puncture was performed in superior-posterior puncture (8.5%) or puncture through the occluder (1.7%). Mean ablation time was 14.9 ± 8.4 minutes, including radiofrequency (83.0%), cryoballoon (11.9%), and pulsed field ablation (5.1%). No major complications were observed, except for 1 transient phrenic nerve palsy during cryoballoon ablation, which recovered intraprocedurally. Voltage mapping revealed no additional substrate related to the occluder. During 12-month follow-up, 7 patients (11.9%) experienced AF recurrence. Conclusion TSP and PVI are safe and can be safely performed in patients with an ASO. No additional substrate related to the occluder was seen. Although no direct comparison was made, outcomes align with existing literature. Further studies are needed.

BACKGROUND:Atrial tachycardia (AT) is commonly observed after orthotopic biatrial heart transplantation (O-BA-HTx). Its clinical presentation, relationship to atrial anastomoses, and electrophysiologic characteristics remain controversial. Novel radiofrequency-guided catheter ablation (RFCA) strategies using electroanatomical mapping and myocardial substrate characterization have emerged, but data on their efficacy in this patient group are scarce. OBJECTIVE:This study aimed to evaluate the efficacy and safety of a novel RFCA strategy for AT in O-BA-HTx patients and assess long-term arrhythmia-free survival. METHODS:Overall, 37 consecutive O-BA-HTx patients with therapy-refractory AT underwent prospectively an RFCA between 2017 and 2024. Procedural parameters, acute and long-term outcomes, and complications were assessed. RESULTS:The cohort (mean age 56.9 ± 16.3 years, 83.8% male) underwent RFCA of AT. Electrophysiologic diagnoses included: The L-line approach, which combines cavotricuspid isthmus and RA-lateral line ablation, was responsible for AT termination in 92.1% (n = 34) of cases. All procedures were performed without any major complications. The median follow-up was 26 months (interquartile range 19-60), and only 2 patients (5.3%) experienced AT recurrence. Remarkably, achieving freedom from AT was associated with freedom from atrial fibrillation, highlighting the effectiveness of addressing AT as a trigger for atrial fibrillation. CONCLUSION:The novel L-Line approach is a safe, effective, and reproducible approach for AT ablation in O-BA-HTx patients, with favorable long-term arrhythmia-free survival.

BACKGROUND Ventricular fibrillation (VF) remains a fatal complication after successful percutaneous coronary intervention (PCI) for ST-elevation myocardial infarction (STEMI). Radiofrequency catheter ablation (RFCA) targeting the Purkinje network and septal substrate shows promise, but clinical data remain limited. OBJECTIVE This study aimed to evaluate the acute and long-term outcomes of RFCA targeting the Purkinje network and septal substrate in patients with STEMI with therapy-refractory VF after successful PCI. METHODS Prospective, multicenter cohort of 13 consecutive patients with STEMI with drug-refractory VF storm despite successful PCI. VF occurred a median of 8 days after STEMI [interquartile range 6-13.5]. All underwent urgent RFCA with high-density left ventricular mapping and Purkinje-targeted septal substrate modification, aiming to eliminate spontaneous VF and achieve acute noninducibility during programmed stimulation. RESULTS The left anterior descending artery was the predominant culprit vessel, identified in 12 of 13 cases (92.3%). Acute procedural success was achieved in all patients (100%). VF recurrence occurred in 1 of 13 (7.7%) during a median 21-month follow-up [interquartile range 14.5-47] and was successfully treated with repeat ablation. Procedure-related complete atrioventricular block occurred in 2 of 13 (15.4%). In-hospital mortality was 2 of 13 (15.4%), owing to stroke and sepsis. CONCLUSION Septal substrate modification targeting the Purkinje network in STEMI patients with therapy-refractory VF- particularly after left anterior descending artery STEMI-may represent an effective therapeutic strategy for arrhythmia control and improved long-term survival. Further studies are needed to confirm these findings.