Ward, Robert C.

BACKGROUND: Ventricular fibrillation (VF) remains a leading cause of sudden cardiac death with an incompletely characterized electrophysiological substrate. Traditional large-animal VF models are limited by hemodynamic collapse and myocardial ischemia. This study establishes a reproducible swine model using dual mechanical circulatory devices to enable high-density electroanatomic mapping under nonischemic conditions. METHODS: Five Yorkshire swine (55–65 kg) underwent sustained VF supported by venoarterial extracorporeal membrane oxygenation (2.5–3.0 L/min) and percutaneous left ventricular unloading (Impella CP, P-2–P-4). High-density electroanatomic mapping using CARTO 7 was performed at baseline and after defibrillation. Bipolar voltage was acquired from 7 predefined ventricular regions (21 measurements per animal per time point; n=210 paired observations). Unipolar voltage mapping and continuous surface ECG monitoring were used to assess acute ischemic injury. Systemic perfusion was maintained at systolic arterial pressure ≥80 mm Hg. Linear mixed-effects modeling was used to analyze voltage changes from pre-VF to post-VF. RESULTS: Sustained VF (10±1 minutes) was reproducibly induced and maintained with consistent hemodynamics (systolic arterial pressure, 90±5 mm Hg; extracorporeal membrane oxygenation flow, 2.5±0.5 L/min). All animals were successfully defibrillated. High-density mapping was feasible in all experiments (1000±300 points per chamber). Bipolar voltage showed no change from pre-VF (5.86±2.56 mV) to post-VF (6.53±2.22 mV; mean difference, 0.67 mV [95% CI, –0.31 to 1.65]; P =0.15). Both left ( P =0.17) and right ventricles ( P =0.08) demonstrated voltage preservation. Regional analysis showed no significant changes (all P >0.05); post-VF voltages remained above viability thresholds (>1.5 mV). Unipolar voltage maps recovered toward baseline, with no ECG injury pattern identified after defibrillation. CONCLUSIONS: Dual mechanical circulatory support with venoarterial extracorporeal membrane oxygenation and Impella CP enables reproducible, high-fidelity electroanatomic mapping and preserves myocardial substrate after sustained VF in a large-animal model. This platform overcomes key technical barriers in VF research, providing a nonischemic foundation for future mechanistic and translational studies.

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.

Introduction: Carcinoid heart disease (CHD) is a rare sequelae of hormonally active neuroendocrine tumors that often requires cardiac surgical intervention. Little is reported on cardiac implantable electronic device (CIED) implantation in the CHD patient population. Hypothesis: We sought to establish the safety and efficacy of CIED implantation in patients with CHD. Methods: We retrospectively reviewed patients with a diagnosis of CHD who underwent CIED implantation at our institution (Mayo Clinic) and evaluated indications for implant, perioperative complications, and mortality. Results: A total of 27 patients with a cumulative follow up of 75 patient-years were identified during the study period. The most common indication for device implant was high grade atrioventricular block (n=18, 66.7%). 14 (51.8%) had baseline conduction disease and 26 (96.2%) underwent cardiac surgery prior to CIED implant. The majority of devices implanted were dual chamber permanent pacemakers (PPM) (n=17, 63.0%), while other devices included single chamber PPM, epicardial PPM, chronic resynchronization devices, and intracardiac defibrillators. Peri-operative complication occurred in 6 patients (22.2%), with 2 patients requiring ICU level care. No patient suffered carcinoid crisis during implantation and there was no peri-implant mortality. Long term, 3 patients required device extraction: 1 for infection, 1 for lead related pain, and 1 for generator migration. The median time to death from implant was 2.5 years, with one-year mortality at 15%. Conclusions: In this unique cohort of patients with CHD, CIED can be performed safely. CIED most often occurred in the post cardiac surgical period and carcinoid crisis was uncommon.

Abstract Introduction Transsubclavian venous implantation of the Aveir leadless cardiac pacemaker (LCP) has not been previously reported. Methods and Results Three cases of transsubclavian implantation of the Aveir LCP are reported. Two cases were postbilateral orthotopic lung transplant, without appropriate femoral or jugular access due to recent ECMO cannulation and jugular central venous catheters. In one case, there was strong patient preference for same‐day discharge. Stability testing confirmed adequate fixation and electrical testing confirmed stable parameters in all cases. All patients tolerated the procedure well without significant immediate complications. Conclusions We demonstrate the feasibility of transsubclavian implantation of the Aveir LCP.

Idiopathic ventricular tachycardia (VT) is an important cause of morbidity and less commonly, mortality in patients with structurally normal hearts. Appropriate diagnosis and management are predicated on an understanding of the mechanism, relevant cardiac anatomy, and associated ECG signatures. Catheter ablation is a viable strategy to adequately treat and potentially provide a cure in patients that are intolerant to medications or when these are ineffective. In this review, we discuss special approaches and considerations for effective and safe ablation of VT arising from the right ventricular outflow tract, left ventricular outflow tract, left ventricular fascicles, papillary muscles, and moderator band.

The preprocedural imaging before the left atrial appendage closure device is critical for selecting the appropriate device for the appropriate patient. CT scans and TEE have been used in the past for preprocedural imaging. In this report, the authors used cardiac MRI as a pre procedural planning tool in the wake of scarcity of contrast availability.

Introduction: Prevention of stroke in patients with atrial fibrillation and cancer is challenging as patients are at increased bleeding and thrombotic risk. Left atrial appendage occlusion (LAAO) has evolved as a promising strategy for stroke prevention with protentional to reduce bleeding risk, though no data exists on its efficacy in patients with cancer. Hypothesis: LAAO is a safe and effective strategy for reducing stroke and bleeding risk in cancer patients with atrial fibrillation. Methods: We retrospectively reviewed all patients with nonvalvular atrial fibrillation who underwent LAAO at all Mayo Clinic sites from 2017-2020 and identified those who had undergone prior or current treatment for cancer. Baseline demographics, malignancy history, atrial fibrillation parameters, procedural success/complications, stroke and bleeding incidence and major adverse cardiac events were ascertained. Results: 55 patients were included in the study; 44 (80.0%) were male and mean age was 79.0 ± 6.1 years. Most common primary malignancies included prostate cancer (29.1%), oropharyngeal cancer (12.7%), and melanoma (10.9%) with 15 (27.3%) having metastatic disease and 14 (25.5%) patients having active malignancy at device implant. Mean CHA2DS2-Vasc score was 4.9 ± 1.3, with 47 (85.5%) patients having a prior bleeding event. Acute procedural success was achieved in all patients with 30-day complications including 4 (7.3%) with vascular access site bleeding, 1 (1.8%) with pericarditis and 1 (1.8%) with a seizure. At a follow up of 1.8 ± 1.1 years, ischemic stroke occurred in 2 (3.6%) patients with bleeding complications in 5 (9.1%) patients. Device related complications occurred in 6 (10.9%) patients with 4 (7.3%) with device thrombosis and 2 (3.6%) with a peri-device leak. Death occurred in 14 (25.5%) patients most commonly due to malignancy progression (9.1%) and infection (7.3%). Conclusions: In our study cohort, LAAO in patients with cancer was achieved with excellent procedural success and offered reasonable reduction in stroke and bleeding risk. Mortality was high likely due to the age of the patients studied, underlying malignancy and comorbidities. Further studies are needed to investigate the prevalence of device thrombosis in cancer patients.