CI-452764-4 OUTCOMES IN PATIENTS WITH HIGH BODY MASS INDEX USING A NOVEL INTERCOSTAL EXTRAVASCULAR ICD LEAD

Abstract

A novel extravascular (EV) ICD lead (AtaCor Medical, San Clemente, CA) is under development for sensing and defibrillation of ventricular tachyarrhythmias (VF) and has been tested in subjects with body mass indexes (BMI) up to 35 kg/m2. Since body habitus can affect extravascular defibrillation effectiveness, it was deemed important to assess this new lead in subjects with high BMI (HBMI). The purpose of this analysis is to assess initial safety and performance outcomes in obese subjects (BMI ≥ 30 kg/m2) compared to non-obese subjects (BMI < 30 kg/m2). Thirty=six (36) human subjects were enrolled in two non-randomized, single-center studies (PASS PULL EV-ICD, NCT0509928 and SECURE EV, NCT05099289) with identical acute testing protocols. Subjects were implanted with an investigational EV-ICD lead, inserted through an intercostal space at the left sternal margin into the anterior mediastinum, and fixated at the fascial plane along the left parasternum. The EV-ICD lead was then tunneled subcutaneously to a left lateral pocket (n=30) or left pectoral pocket (n=6). EV-ICD Leads were connected to DF-4 compatible ICD pulse generators for acute sensing and defibrillation testing. Defibrillation testing started at 30 Joules (J) and stepped down in 10 J increments following conversion success and stepped up in 5 J increments following conversion failure. Automatic sensing and detection algorithms were relied upon for the first ICD shock unless manual commanded shocks were necessary due to suspected undersensing. For this analysis, the cohort was split into subgroups of low BMI < 30 (n=23) and high BMI ≥ 30 (n=13) to assess differences related to body habitus. Low BMI (LBMI) and HBMI, subgroups were similar by gender (22% vs 23% female), age (mean 57 yrs vs 60 yrs) and mean LVEF (39% vs 37%), respectively. Median time to lead placement was similar (11.5 min vs 10.3 min), as was the lowest energy required for defibrillation of induced VF with a left midaxillary ICD (LBMI = 16.4 J vs HBMI = 16.2 J). Sensing was 100% appropriate in both groups, with similar time-to-therapy (LBMI = 10.1 s vs HBMI = 11.5 s). In this limited size cohort, serious adverse events related to the investigational device or procedure were indifferent (LBMI = 2 subjects (9%) vs HBMI = 0). A left, anterior parasternal EV ICD lead inserted via an intercostal space was safe and effective at automatically sensing, detecting and defibrillating induced VT/VF in both low and high BMI subjects.