Mulpuru, Siva K.

ABSTRACT Background Pulsed field ablation (PFA) is an emerging non‐thermal ablation modality with proven safety in atrial arrhythmia ablation. However, data on its performance for ventricular arrhythmias (VA) remain limited. Objective To evaluate the feasibility, safety, and efficacy of PFA for complex VA in a multicenter real‐world US registry. Methods This retrospective study included consecutive patients undergoing PFA for ventricular tachycardia (VT) or premature ventricular contractions (PVCs) at three Mayo Clinic centers (April 2024 to July 2025). The primary feasibility outcome was the successful delivery of PFA lesions to the intended target substrate. Primary efficacy outcomes included acute procedural success; sustained VT recurrence requiring implantable cardioverter‐defibrillator (ICD) shocks or multiple antitachycardia pacing therapies; and ≥ 80% reduction in PVC burden. Safety outcomes included procedural complications, valvular function, thromboembolic events, renal function, and conduction disturbances. Results Twenty‐six patients were included (13 PVC, 13 VT). Acute success was achieved in all VT ablations (69.2% complete; 30.8% partial) and in 92.3% of PVC ablations. Complications occurred in 11.5% of patients (transient LBBB [ n = 1] and vascular complications [ n = 2]). No thromboembolic events, intracardiac thrombus, or acute kidney injury were observed. Lesions near the mitral valve apparatus did not worsen mitral regurgitation, including in patients with pre‐existing valve disease. After a median follow‐up of 365 days, one patient experienced VT recurrence requiring ICD shocks. Estimated recurrence‐free survival after VT ablation was 61.5% at 12 months; 58.3% of PVC patients achieved ≥ 80% burden reduction. Conclusion PFA for VA appears feasible and acutely effective, with a low rate of procedure‐related complications. While acute success was high, long‐term outcomes were acceptable for VT ablation and relatively modest for PVC ablation, highlighting the need for continued refinement of technology and energy‐delivery strategies. Larger prospective studies are warranted.

BACKGROUND: It is unknown whether cardiac resynchronization therapy (CRT) improves systemic metabolomic profile by enhancing left ventricular function. The observational cohort study aimed to investigate the effect of CRT on left ventricular ejection fraction (LVEF) and circulating plasma metabolites in patients who had heart failure with reduced LVEF. METHODS: We prospectively screened patients with ischemic cardiomyopathy and nonischemic cardiomyopathy who received CRT with a defibrillator for LVEF ≤35% according to current guidelines. Clinical assessment included echocardiography and device interrogation. Blood samples for metabolomic analysis were collected before CRT and at 6-month follow-up. Plasma was subjected to gas chromatography-mass spectrometry and 1 H nuclear magnetic resonance-based metabolomic analysis. RESULTS: Totally 92 patients were enrolled, with a mean age of 67.3±11.3 years (37.0% female). LVEF was significantly improved from 28.9±7.6% at baseline to 36.0±11.3% at 6 months ( P <0.001) and to 40.1±12.6% at 12 months ( P <0.001). After CRT, 42 metabolite features were significantly decreased compared with the baseline. The ketone bodies, including 3-hydroxybutyrate ( P <0.001) and acetone ( P =0.01), were reduced. A branched-chain amino acid, isoleucine, was also decreased after CRT ( P =0.01). These metabolomic changes were mainly observed in the nonischemic cardiomyopathy group, while the metabolomic profile in the ischemic cardiomyopathy group was characterized by enhanced amino acid oxidation and elevated levels of lactate and pyruvate. The improvement in LVEF positively correlated with the ratio of changes in ketone bodies and isoleucine. CONCLUSIONS: CRT may modulate the systemic plasma metabolomic profile, which correlated with improvement in left ventricular function in patients with severe heart failure with reduced ejection fraction.

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 Background The extravascular implantable cardioverter defibrillator (EV-ICD) was designed to avoid lead-related complications associated with transvenous systems and deliver features such as anti-tachycardia pacing (ATP) and reduced generator size that provide an advantage over a subcutaneous ICD (S-ICD). As such, the EV-ICD is an attractive alternative for younger patients with genetic heart diseases (GHDs) who are not in need of permanent pacing. Objective To examine the indications, complications, and the clinical outcomes of patients with GHDs who received an EV-ICD. Methods A retrospective review of the electronic record was done for all GHD patients evaluated in genetic heart rhythm and/or cardiomyopathy clinics who had an EV-ICD implanted between 1/2021 and 2/2025. Basic demographic, ICD indications, complications, and therapy data were then extracted for all study patients. Results Overall, 23 patients (35% female; mean age 39 ± 16 years; 61% with a disease-causative genetic variant; mean LVEF 57%) with an underlying GHD (hypertrophic cardiomyopathy in 9, arrhythmogenic cardiomyopathy in 8, idiopathic ventricular fibrillation in 3, dilated cardiomyopathy in 2, and long QT syndrome in 1) had an EV-ICD implanted. For the majority, an EV-ICD was implanted for primary prevention (15/23; 65%) and represented their first ICD system (21/23; 91%). The success rate of the procedure was 96% with only one abandoned procedure because of poor R-wave sensing. Inadvertent intraprocedural lead placement in the pericardial space occurred in 1 patient with previous thoracotomy and surgically placed epicardial lead without sequelae or need for revision. Over a mean follow-up of 8±9 months, the rate of complications was low (1/23; 4%) with one electrode displacement and this patient underwent defibrillation threshold testing (DFT), the device properly detected VF and emitted a successful shock 30 J. Thus far, 2 patients have received appropriate VT/VF-terminating therapies (3 ICD shocks, 0 ATP) with successful conversion to sinus rhythm. One patient died following an electrical storm. One patient had 3 inappropriate ICD shock for sinus tachycardia while exercising followed by 1 successful shock for VF. Conclusion In this early experience, EV-ICDs appear to be safe and effective in younger patients with genetic arrhythmogenic and hypertrophic cardiomyopathies. Future studies are needed to better understand the utility of EV-ICDs in patients with cardiac channelopathies and advantages of EV-ICDs over transvenous and S-ICD systems in patients with an array of sudden death-predisposing GHDs.

ABSTRACT Background Transvenous lead removal (TLR) in patients with a history of mediastinal radiation poses unique challenges due to potential radiation‐induced fibrosis, vascular changes, and anatomical distortion, which may increase procedural complexity and complication risk. However, contemporary data on clinical outcomes in this population remain limited. Methods We analyzed the National Readmissions Database (2016–2021) to identify adults (≥ 18 years) undergoing TLR. Patients were stratified by prior mediastinal radiation. Baseline characteristics were compared using standard statistical tests. Multivariable logistic regression was used to evaluate the association between prior mediastinal radiation and in‐hospital outcomes, 30‐day mortality, and 30‐day readmissions after adjustment for demographics and comorbidities. Results A total of 48,985 patients underwent TLR, of whom 735 (1.5%) had a history of mediastinal radiation. Compared with patients without radiation, those with prior radiation were older (70.1 vs. 66.2 years, p < 0.01), were more frequently females (38.2% vs. 31.6%, p < 0.01), and had higher rates of valvular heart disease, atrial fibrillation, and peripheral vascular disease. Adjusted analyses demonstrated no increased risk of in‐hospital mortality (2.3% vs. 3.4%; adjusted odds ratio [aOR] 0.65, 95% confidence interval [CI] 0.41–1.18, p = 0.29) or major complications, including cardiac arrest, pericardial complications, vascular injury, pulmonary complications, or embolic events. Similarly, (3.6% vs. 5.3%; aOR 0.76, 95% CI 0.48–1.43, p = 0.35) and 30‐day all‐cause readmissions (8.7% vs. 9.1%; aOR 0.81, 95% CI 0.64–1.28, p = 0.70) were not significantly different between groups. Subgroup analyses by indication for TLR (infection vs. mechanical complication) revealed no differences in outcomes. Conclusion Despite theoretical concerns, prior mediastinal radiation was not associated with excess procedural risk or worse short‐term outcomes after TLR. These findings may inform procedural planning and risk counseling in clinical practice.

Abstract Aims The increasing adoption of transcatheter tricuspid valve replacement (TTVR) offers a promising therapeutic option for patients with severe tricuspid regurgitation. However, many of these patients have pre-existing cardiac implantable electronic devices (CIEDs), raising concerns about potential lead-related complications. Despite these concerns, limited data exist on the impact of TTVR on CIED integrity and function. This study aimed to evaluate the impact of TTVR on CIED lead function, including pacing thresholds, sensing, and impedance, in patients undergoing TTVR with the EVOQUE valve system. Methods and results A retrospective observational study was conducted at Mayo Clinic Rochester, including 32 consecutive patients who underwent TTVR with pre-existing CIEDs. A total of 32 patients were included, with a mean age of 79.2 ± 8.4 years; 59% were female. A total of 62.5% had a permanent pacemaker, 12.5% had an implantable cardioverter-defibrillator, 15.6% had a cardiac resynchronization therapy pacemaker, and 9.4% had a cardiac resynchronization therapy defibrillator. Following TTVR, 10 (31%) of patients developed lead function changes during a median device follow-up of 210 days (IQR: 43–307 days). The right ventricular lead was primarily affected, with only one case involving an atrial lead. Neither the Ottawa score nor the anatomical lead position reliably predicted lead abnormality (P = 0.86 and P = 0.53, respectively). R-wave sensing changes were the most common lead change observed, affecting 55% of cases. In 67% of these cases, R-wave sensing alterations occurred as an isolated finding, with no significant change in impedance or thresholds, and were managed conservatively without any need for device reprogramming. Four patients (13%) had findings concerning for a lead insulation breach, in which one (3%) required a lead revision. Among five patients with follow-up exceeding 600 days, two patients exhibited a statistically significant gradual decline in impedance without other lead dysfunction, suggesting potential subclinical lead degradation. Conclusion Transcatheter tricuspid valve replacement with the EVOQUE system in the setting of cardiac device leads is associated with lead function changes in 31%. The majority of lead-related changes were managed conservatively, but 13% of patients had findings concerning for an insulation breach. Future studies should focus on refining implantation techniques and defining optimal strategies for managing device-lead interactions in this population.

ABSTRACT Introduction Lead‐related venous obstruction is a significant complication of chronic indwelling transvenous leads, which poses unique challenges during cardiac device upgrades. Background The anatomical sequelae of venous occlusion are variable and carry important procedural implications. Occlusions can develop in any part of the venous system, but they most often occur in the subclavian and innominate veins, while the superior vena cava is less frequently affected. Methods In this review, we describe approaches to lead‐related venous occlusion providing step‐by‐step procedural guidance. Results Venoplasty, neovascular channel creation are two main techniques for addressing lead‐related venous obstruction. Conclusion Venoplasty in the setting of an indwelling pacemaker or defibrillator leads can be performed safely and effectively. The difficulty of the procedure lies in crossing the obstruction. Familiarity with various tools is needed for a successful outcome.

ABSTRACTIntroductionDry epicardial access to facilitate epicardium mapping and ablation is a well described technique with increasing use in modern electrophysiology. However, traditional percutaneous access can be challenging is obese patients or those with anatomical variations.Methods and ResultsWe report on a case where a subxiphoid cut down was utilized for epicardial access in a patient with morbid obesity. This approach allows us to reach the epicardial space when traditional needles do not suffice and enables a more controlled access, potentially minimizing the risk of damage to nearby structures.ConclusionSubxiphoid cut down to facilitate percutaneous epicardial access is a simple and effective option when traditional epicardial access is not feasible due to morbid obesity or anatomical variations.