Abstract 13750: Substernal Extravascular Implantable Cardioverter-Defibrillator System Infection in Large Animals

Background: The Extravascular ICD (EV ICD) with substernal lead placement may provide clinical advantages to transvenous and subcutaneous systems. An understanding of substernal infection manifestation and treatment is required. Methods: The EV ICD system was implanted in 13 large animals (canine, porcine, ovine), and porcine were co-implanted with a transvenous CRT-D system. Animals were monitored for clinical presentation of infection over 12-18 weeks of follow-up, and cultures were collected to confirm infection. Treatment was bifurcated, with some animals receiving antibiotics while EV ICD leads remained in situ , and other animals treated with system removal and antibiotics. Histopathology was conducted at the end of study. Results: Five infections were confirmed over the course of study, 4 of which involved infection of the EV ICD system and 1 of which involved infection of only the concomitantly implanted CRT-D system without infection of the EV ICD system. Two of the EV ICD-related infections were treated with system removal and antibiotic course, and both infections resolved. Two additional EV ICD-related infections were treated with antibiotics alone without explant of the EV ICD leads; histology showed that neither infection resolved. The transvenous CRT-D system infection progressed to septicemia and endocarditis, requiring early study end. No EV ICD-related infection progressed to blood stream infection, and the sternal bone did not become infected when infection was present in the substernal tissues. Conclusions: Study findings suggest that EV ICD-related infections are treatable with system removal and antibiotic therapy.