BACKGROUND: Implantable cardiac defibrillators (ICDs) are essential for preventing sudden cardiac death. Despite inclusion in national guidelines, older adults are often underrepresented in trials. Evaluating ICD use in the aging population, particularly with advancements in heart failure treatment, is crucial. OBJECTIVE: This study examines outcomes in octogenarians undergoing ICD implantation for primary and secondary prevention, focusing on ICD therapies and mortality timing. METHODS: A retrospective observational study at a single Canadian academic center included patients ≥80 years old at ICD implantation, excluding those with <
30 days follow-up. Data on demographics, comorbidities, mortality, and ICD therapies were collected from electronic medical records. Clinical frailty was assessed using the Dalhousie Clinical Frailty Scale. RESULTS: We identified 143 patients (mean age 82.6 ± 2.2 years, 14% female) from May 2015 to October 2023. ICDs were implanted for primary prevention in 63 patients (44%) and secondary prevention in 80 patients (56%). Thirty-seven patients were excluded due to insufficient follow-up. ICD therapies occurred in 30 patients (25%) through anti-tachycardia pacing (ATP) and in 19 patients (18%) through shocks. The mean time to first ATP was 16.9 ± 21.0 months, and to first shock, 21.2 ± 23.6 months. Among 66 patients with mortality data, 19 (24%) died at 31.3 ± 30.4 months. Patients with non-ischemic cardiomyopathy experienced earlier shocks (7.7 vs. 32.2 months, CONCLUSION: Elderly patients undergoing ICD implantation have multiple comorbidities and competing causes of mortality. Device use is overall infrequent but occurs well before observed mortality. Prospective clinical trials are needed to determine ICD benefits in this age cohort.