4D robust evaluation for the intensity-modulated-proton-radiotherapy plans for patients with ventricular tachycardia based on cardiopulmonary motion characteristics.

The use of cardiac stereotactic body radiation therapy for the treatment of ventricular tachycardia (VT), also termed stereotactic ablative radiation therapy or, increasingly, stereotactic arrhythmia radioablation (STAR), is increasingly used in select patients. STAR has emerged as a promising alternative to invasive catheter ablation (CA) for patients with high-risk refractory VT who have failed prior medical therapy or catheter ablation. Since the publication of the first case series using STAR, our understanding of the mechanisms of STAR, longer-term clinical outcomes, potential side effects, and barriers to widespread adoption of cardiac radioablation has become increasingly clear. In this review, we discuss these topics, the increased adoption of STAR, as well as the challenges that lie ahead for this therapy. In addition, as data strongly suggest that fibrosis alone cannot account for the early decreases in VT events observed post-STAR, we propose adopting the STAR acronym to instead stand for stereotactic arrhythmia radiation therapy.

Characterization of external defibrillator output and its impact on defibrillation protection of medical equipment.

P39. Transcatheter Delivery of Extracellular Vesicles from Cardiosphere-derived Cells Reduces Recurrent Ventricular Tachyarrhythmias after Myocardial Infarct

The Long-Term Clinical Progression of Genotype-Positive/Phenotype-Negative Patients With Hypertrophic Cardiomyopathy.

Cardiovascular Magnetic Resonance-based Tissue Characteristics and Clinical Outcomes in Apical Hypertrophic Cardiomyopathy.

High-efficiency enzymatic conversion of cellulose to starch by strengthening glucose-utilization bypass.

Right-sided ST-segment elevation is typically associated with inferior myocardial infarction; however, the clinical significance of synthesized right-sided ECG leads in anterior ST-segment elevation myocardial infarction (STEMI) remains unclear. This study investigated the clinical implications of ST-segment elevation in the synthesized V4R lead in patients with anterior STEMI undergoing primary percutaneous coronary intervention (PCI). We retrospectively analyzed patients with anterior STEMI who underwent primary PCI and had synthesized right-sided ECG leads recorded on admission. Patients were classified according to the presence or absence of ST-segment elevation in synthesized V4R. Clinical characteristics, angiographic findings, and in-hospital outcomes were compared between groups. Patients with synthesized V4R ST-segment elevation exhibited significantly higher peak creatine kinase levels, indicating larger infarct size. They also had a higher incidence of ventricular tachyarrhythmias and cardiogenic shock requiring mechanical circulatory support. In an additional stratified analysis limited to patients with higher peak creatine kinase levels, ventricular arrhythmias and cardiogenic shock remained more frequent in the V4R-positive group despite comparable peak creatine kinase levels and left ventricular ejection fraction between groups. Furthermore, a right ventricular branch originating from the left anterior descending artery was more frequently observed in patients with V4R elevation. Synthesized V4R ST-segment elevation in anterior STEMI is associated with larger infarct size and an increased risk of ventricular tachyarrhythmias and cardiogenic shock. This finding may help identify patients who are particularly vulnerable to acute electrical and hemodynamic instability during the early phase of myocardial infarction.

Adjunctive Purkinje Denetworking During Ventricular Tachycardia Ablation in Patients With Prior Ventricular Fibrillation.

Cardiac fibromas are known to be rare and have a mostly benign nature. Despite their benign histopathology, fibromas may become clinically significant by exerting compression or inflow-outflow occlusion, considering their size and location. Therefore, the risks for malignant arrythmias, especially ventricular tachycardia, syncope and sudden cardiac deaths increase significantly. Given their possible arrhythmogenic nature, surgical resection of cardiac fibromas remains the definitive treatment to tackle these fatal complications. We present surgical management of a young adult female patient with a large interventricular fibroma causing multiple episodes of ventricular tachycardia and syncope.

Ventricular tachycardias represent a complex clinical challenge, particularly due to the intricate arrhythmic circuits and diverse substrates found in ischemic and non-ischemic cardiomyopathies. This review explores the significant advancements in mapping, imaging, and ablation technologies that have transformed the management strategies for ventricular arrhythmias. Recent innovations such as pulsed-field ablation and high-resolution imaging modalities like cardiac magnetic resonance and multi-detector computed tomography have refined our approach to ablate ventricular tachycardias. The evolution of surgical and hybrid ablation techniques also highlights an adaptive response to cases unmanageable by conventional interventions. Furthermore, we discuss the integration of new diagnostic tools and detailed substrate analysis, which are pivotal in enhancing procedural outcomes and reducing recurrence. This synthesis of current practices with emerging technologies offers a promising direction toward more effective and personalized management of VT, underlining the need for continuous advancement in both technological capabilities and procedural strategies.

Overdoses of extended-release (ER) medications can cause life-threatening toxicity from prolonged gastrointestinal drug retention due to pharmacobezoar formation. This may result in severe complications including delayed serotonin syndrome and intestinal ischemia despite early use of enhanced elimination strategies. A 45-year-old woman presented with altered mental status following carbamazepine-venlafaxine ER overdose. Initial carbamazepine concentration was 163 μmol/L. She suffered a ventricular tachycardia arrest requiring venoarterial extracorporeal membrane oxygenation and enhanced elimination with continuous renal replacement therapy (CRRT). After CRRT, carbamazepine concentration rebounded from 33 to 80 μmol/L and clinical features of serotonin syndrome developed suggesting ongoing absorption. CT revealed cecal pneumatosis with obstruction. Laparotomy at day 9 revealed transmural ischemic necrosis with 4-6 L of retained charcoal and polyethylene glycol mixture; source control required a right hemicolectomy. Carbamazepine concentration declined postoperatively and serotonergic symptoms resolved. Carbamazepine-venlafaxine ER overdose with retained pill fragments can cause a variety of complications including prolonged toxicity. Rebounding drug concentration following enhanced elimination should trigger an investigation for gastrointestinal sequestration and prompt surgical consultation.

Prompt recognition and treatment of hyperkalemia-induced arrhythmias in children is vital, as these can be life-threatening. Tumor lysis syndrome (TLS) can present with severe hyperkalemia, which, if untreated, may lead to renal failure, arrhythmias, or multi-organ failure. Simulation offers a safe way for providers to practice managing such acute scenarios. While prior simulations address hyperleukocytosis, few focus on metabolic complications like hyperkalemia in spontaneous TLS. This high-fidelity simulation aimed to improve participants' confidence in recognizing and managing pediatric ventricular tachycardia due to hyperkalemia from TLS. This prospective simulation-based study was conducted by pediatric emergency, general emergency, and hematology-oncology physicians who developed the simulation for pediatric and emergency medicine providers. Participants managed a case of a school-aged child with hyperkalemia-induced arrhythmia due to spontaneous TLS, progressing to oliguria. Conducted in a simulated ED setting with a high-fidelity manikin, the scenario required clinical interpretation and intervention. The primary outcome was participant self-reported confidence in recognizing and managing hyperkalemia-induced ventricular tachycardia in the context of TLS. Secondary outcomes included objective critical action performance metrics, including time to arrhythmia recognition, time to recognition of anuria, and differential diagnoses generated during the scenario. A structured debrief, following the Promoting Excellence and Reflective Learning in Simulation (PEARLS) framework, followed each session with content expertise provided by a pediatric hematology/oncologist. Participants completed post-simulation surveys on confidence, practice impact, and feedback. Data was analyzed descriptively, with results reported as frequencies or percentages. Ninety-twoparticipants completed the survey. Fewer than 25% had previously managed TLS or related arrhythmias. A total of 99% (N=91) found the simulation relevant, and 83% (N=76) reported increased confidence in recognizing and managing ventricular tachycardia due to hyperkalemia. This descriptive study demonstrated the effectiveness of high-fidelity simulation in improving provider confidence and preparedness for managing rare, high-acuity presentations such as spontaneous TLS with hyperkalemia-induced ventricular tachycardia. Participants valued its relevance, realism, and applicability. These findings lay the groundwork for future comparative and longitudinal research, including in situ implementation with interdisciplinary teams.

Abstract Background Left posterior fascicular ventricular tachycardia (LPF-VT) is considered the most common type of fascicular ventricular tachycardia. False tendons (FTs) are reported to be common in patients with LPF-VT and may contribute to the pathogenesis of this condition. However, LPF-VT cases with congenital septal structural abnormalities have not been reported. Case summary This case report investigated an 86-year-old woman diagnosed with LPF-VT and underwent radiofrequency ablation. The preoperative transthoracic echocardiography (TTE) results indicated no anatomic abnormalities. During the procedure, the intracardiac echocardiography (ICE) revealed a fissure within the ventricular septum. The successful ablation site was precisely located at the left orifice of this fissure. To improve treatment efficacy, the catheter was advanced into the fissure to continue ablation. One month postoperation, the patient presented with mild shortness of breath after activity. The TTE revealed a 15 × 16-mm iatrogenic ventricular septal defect (VSD) with a pulmonary artery pressure (PAP) of 48 mmHg. Percutaneous VSD closure resolved the symptoms, and the PAP returned to normal. During the follow-up period, no recurrence of palpitations or dyspnea was observed. Discussion Macro-reentry has been suggested as the mechanism of LPF-VT, as FTs can provide an electro-anatomical substrate for LPF-VT. In the present case, the re-entrant circuit of LPF-VT may be associated with the rare anatomic anomaly, although a definitive link remains unestablished. Additionally, extreme caution should be exercised during catheter manipulation to prevent iatrogenic injuries.

Abstract Background and Aims Stereotactic arrhythmia radioablation (STAR) is increasingly used for refractory ventricular tachycardia (VT), yet prospective multicentre outcome data remain limited. Here, the planned interim analysis of the prospective Standardized Treatment and Outcome Platform for Stereotactic Therapy Of Re-entrant tachycardia by a Multidisciplinary (STOPSTORM) registry is reported. Methods STOPSTORM is a European prospective, international, multicentre registry of patients treated with STAR. The primary efficacy endpoint was the change in sustained VT episode burden comparing the 6 months before versus the 6 months after STAR. The primary safety endpoint was the occurrence of serious adverse events (SAEs) adjudicated as possibly or probably treatment-related. Overall survival was assessed using time-to-event methods. Results Across 28 centres, 193 patients were included (mean age 68±9 years; 88% male; 53% non-ischaemic cardiomyopathy). Median follow-up was 19 months. Among 107 evaluable patients with ≥6-month follow-up, the median VT episode burden was reduced by 80% after STAR. Among patients surviving ≥6 months, 72% were free from implantable cardioverter-defibrillator (ICD) shock. In the full cohort, 12 SAEs were adjudicated as possibly or probably treatment-related, including pericardial effusion, coronary events, and early post-treatment ventricular arrhythmia. Overall survival probability was 77% at 12 months. Conclusions In the largest prospective multicentre cohort reported to date, STAR was associated with a substantial reduction in VT burden and ICD shocks, with a low frequency of possibly or probably treatment-related SAEs.

Background: Arrhythmia is a common and clinically significant complication during hospitalization for ST-segment elevation myocardial infarction (STEMI). This study aimed to identify factors associated with the occurrence of arrhythmia in the acute phase of STEMI. Methods: This single-center cross-sectional study was conducted among adult patients hospitalized with STEMI. Demographic and clinical variables, including cardiovascular risk factors and disease severity (Killip class, Thrombolysis in Myocardial Infarction [TIMI] score, and Global Registry of Acute Coronary Events [GRACE] score), were obtained from medical records. The primary outcome was in-hospital arrhythmia, defined as documented atrial or ventricular tachyarrhythmia or clinically significant bradyarrhythmia. Factors associated with arrhythmia were assessed using bivariate analyses followed by multivariable logistic regression. Results: This study involved 113 patients, with a mean age of 56.4 (11.1) years. Arrhythmia occurred in 26.5% (30 patients) during hospitalization. In bivariate analyses, arrhythmia was associated with higher Killip class (P<0.001), higher TIMI score (P=0.005), higher GRACE score (P=0.001), lower tricuspid annular plane systolic excursion (P=0.002), elevated serum potassium level (P=0.010), and impaired renal function, reflected by higher urea (P=0.005) and creatinine levels (P = 0.004). After multivariable adjustment, only Killip class remained independently associated with arrhythmia: patients presenting with Killip class I had a significantly lower risk of arrhythmia than those with higher Killip classes (adjusted OR, 0.404; 95% CI, 0.20 to 0.80; P=0.009). Conclusion: In hospitalized patients with STEMI, arrhythmic risk is chiefly driven by early clinical severity. Killip class is a simple bedside predictor of in-hospital arrhythmia and can aid early risk stratification and monitoring.

Patients with cardiac sarcoidosis (CS) and mildly impaired left ventricular ejection fraction remain at high risk for sudden cardiac death. However, risk stratification for implantable cardioverter-defibrillator implantation in this group is needed. We aimed to determine if electrophysiologic study (EPS) may be used as a noninvasive alternative for sudden cardiac death risk stratification. In this retrospective cohort study, we analyzed patients with CS (aged >18 years) with highly probable or probable sarcoidosis according to the World Association of Sarcoidosis and Other Granulomatous Disorders Sarcoidosis Organ Assessment Instrument, with evidence of late gadolinium enhancement on cardiac magnetic resonance imaging in a pattern consistent with CS and left ventricular ejection fraction ≥40%, who underwent EPS. We identified 101 patients with CS, 15 EPS positive and 86 EPS negative. A higher proportion of patients with an EPS-positive study was associated with antiarrhythmic therapy (P=0.005) and ventricular tachycardia on ECG or Holter monitoring (P<0.001). In multivariable analysis, transmural myocardial scarring (odds ratio, 3.78 [95% CI, 1.05-14]; P=0.041) and edema on T2-weighted cardiac magnetic resonance imaging (odds ratio, 4.75 [95% CI, 1.09-21.2]; P=0.036) were associated with higher odds of an EPS-positive study. There was no association between anatomic distribution of scar within left ventricular and right ventricular segments and inducibility on EPS. In patients with CS and mildly impaired left ventricular ejection fraction, we demonstrated that transmural myocardial scarring and edema on T2-weighted cardiac magnetic resonance imaging are associated with sustained ventricular arrhythmia during EPS, suggesting that noninvasive imaging features may be used as prognostic indicators in patients with CS. Larger, prospective studies are needed to inform implantable cardioverter-defibrillator implantation guidelines.

Efficacy of bipolar radiofrequency ablation (BA) is often limited by high impedance between the two ablation catheters in cases of therapy-refractory ventricular tachycardias. Tripolar ablation (TA) is a novel approach, adding a dispersive return electrode to BA. The study aimed to investigate differences in lesion growth and geometry in BA and TA using variable power (20-50W) during power-controlled, irrigated radiofrequency ablation on cross-sections of porcine heart preparations in an ex-vivo model. Using high-resolution imaging at one-second intervals, 1694 measurements in 40 lesions were analyzed regarding lesion geometries and ablation parameters. Baseline impedance was lower in TA (213.1 ± 20.6 Ω vs. 242.7 ± 23.6 Ω, p < 0.001) and distinct differences in lesion geometry were present. Specifically, TA produced deeper and wider lesions at the active catheter compared to the return catheter, resulting in trapezoidal lesions in contrast to rectangular lesions in BA. All lesions reached transmurality; however, lesion width continued to increase in BA and TA after transmurality had been achieved. The majority of steam pops (16/18) occurred above 40W without differences in BA and TA. In cases of high baseline impedance, TA using an additional dispersive return electrode seems effective. In this experimental setup, TA creates trapezoidal lesions in contrast to rectangular lesions in BA without an associated increase in the risk of steam pops.

Background: Pediatric out-of-hospital cardiac arrest (OHCA) is rare and associated with poor outcomes. Evidence from physician-staffed EMS systems remains limited. This study aimed to describe the incidence, presenting rhythms, EMS response intervals, and outcomes of pediatric OHCA, and to describe incidence, presenting rhythms, EMS response intervals, and prehospital outcomes in a local physician-staffed EMS system. Methods: We conducted a retrospective study of all pediatric (0-17 years) OHCA cases managed by the ASL Lecce physician-staffed EMS (southern Italy) between 2013 and 2025. Data were abstracted from standardized records. Variables included demographics, initial rhythm, EMS response intervals, temporal patterns, and return of spontaneous circulation (ROSC). The primary outcome was ROSC during prehospital care. Results: Twenty-seven cases were identified, corresponding to a cumulative incidence of 22.9 per 100,000 children over the study period (annualized incidence 1.73 per 100,000 children-year). Mean age was 11.9 ± 5.5 years (median 15); 59% were male. Initial rhythms were asystole in 81% and ventricular fibrillation (VF) in 19%; no pulseless ventricular tachycardia (pVT) or pulseless electrical activity (PEA) were recorded. Five patients had shockable rhythms, with seven shocks delivered overall. Mean time intervals were: event-to-call 1.0 ± 0.6 min, call-to-arrival 10.3 ± 4.1 min, event-to-arrival 11.3 ± 4.4 min. Arrests clustered during daytime (63%) and summer (41%). ROSC occurred in three patients (11%), two with VF and one with asystole; all arrests with ROSC were daytime events. In descriptive comparisons, ROSC cases showed a shorter call-to-arrival interval (T1-T2), whereas no consistent pattern was observed across all prehospital time intervals. Conclusions: Pediatric OHCA in this Italian physician-staffed EMS was infrequent, usually presented with asystole, and rarely achieved ROSC. Shockable rhythms were associated with better outcomes. Given the small sample size, findings related to response times should be interpreted with caution. System preparedness should include pediatric-specific training, early defibrillation access, and multicenter registries to improve care and track outcomes.

The ryanodine receptor 2 gene mutation associated with catecholaminergic polymorphic ventricular tachycardia is one of the aetiologies of cardiac syncope and has the risk of sudden cardiac death. This study reported two novel ryanodine receptor 2 gene variants. We described two 9-year-old girls with recurrent syncope during exercise or stress presenting two novel ryanodine receptor 2 gene variants (c.6938T>G/p. Val2313Gly and c.12263A>C/p. His4088Pro) associated with catecholaminergic polymorphic ventricular tachycardia through a comprehensive review of medical history, examination findings and genetic testing. Propranolol was used for treatment, and the two patients didn't experience episodes of syncope during follow-up for 6 months. Besides, literature associated with catecholaminergic polymorphic ventricular tachycardia and ryanodine receptor 2 mutations was reviewed. Recurrent syncope during exertion or stress should be focused on catecholaminergic polymorphic ventricular tachycardia caused by ryanodine receptor 2 gene mutations. The genetic testing is a crucial tool in confirming the mutation of catecholaminergic polymorphic ventricular tachycardia. Early recognition of this disease, timely diagnosis of ryanodine receptor 2 gene mutations, and administration of appropriate pharmacological agents or ICD implantation are critical to ensure favourable clinical outcomes.