Abstract 4368552: Management of unsuccessful defibrillation therapy in patients with implantable cardiac devices

Background: Unsuccessful defibrillation therapy in patients with implantable cardiac defibrillators (ICDs) and ventricular tachytherapies may occur due to patient and/or device related factors; appropriate management strategies after failed defibrillation therapy have been incompletely described. Objectives: To report on the management and outcomes of patients with implantable cardiac devices and unsuccessful defibrillation therapies. Methods: A single-center cohort of patients with ICDs was examined, patients with unsuccessful ICD therapies were included. Demographic and device features, and survival free from recurrent unsuccessful device therapy was examined among patients undergoing operative versus non-operative management. Results: Among 1449 patients with ICDs, 40 patients (2.8%) were identified with unsuccessful defibrillation therapies (mean age 59±15 years, ejection fraction 29±16%, ischemic cardiomyopathy n=27, 67.5%, secondary prevention device placement n=22, 55%, transvenous ICD n=34, 85%, subcutaneous ICD n=6, 15%). Nonoperative management strategies included device reprogramming (n=8), addition of a class III anti-arrhythmic (n=7), or conservative therapy (n=5). Operative management included addition of a transvenous lead (n=10), addition of subcutaneous array (n=8), or change in pulse generator (n=2). A single-coil device was present in 18/20(90%) patients undergoing operative management compared to 10/20(50%) with non-operative management (P<0.05). There were no other demographic or device differences between the two groups. After 2.4±2.1 years follow up, repeat VT occurred in 22 patients (55%) including 6 patients (15%) with a repeat failed defibrillator therapy. There were no differences in the risk of recurrent failed shocks among patients with operative vs non-operative management (log rank p=0.14). Conclusions: Among a large cohort of patients with ICDs, the incidence of failed defibrillator therapy was 2.8%. With appropriate patient selection, both operative and non-operative management led to similar long-term outcomes; however, the overall incidence of repeat failed defibrillation therapy remained high at 15%, highlighting the need for continued innovation in ICD therapies and the need for rhythm control in this high-risk group.