Project Summary / Abstract X Over 50,000 implantable cardioverter-defibrillators (ICDs) are implanted annually in patients ≥65 years old at an estimated cost of >$2 billion. ICD guidelines draw upon trials enrolling few older patients, yet half of these patients will either be dead or enrolled in hospice within 5 years of implantation. Though Medicare now mandates shared decision-making (SDM) for ICDs, few studies have investigated questions vital for older patients, including health status trajectories and quality of life. Improved SDM for older patients requires moving beyond average treatment effect estimates to incorporate precision modeling of these outcomes. There is therefore a pressing need for longitudinal data to support patient-centered SDM for older adults. To extend our prior work and further improve SDM for older adults considering an ICD, we propose the TRAjectories and Clinical ExpeRiences of ICD Therapy (TRACER-ICD) Study, a multi-center prospective cohort with the goal of better defining patient-centered goals and experiences in older patients undergoing ICD implantation. We will prospectively collect data on geriatric conditions and quality of life from patients at 5 sites, enriched with remote monitoring data on arrhythmias and physical activity, to evaluate their clinical and functional trajectories (Aim 1). This cohort will support further refinement of our statistical model to personalize prediction of treatment outcomes (Aim 2). Lastly, we will use mixed methods to identify optimal implementation strategies for translating these individualized prediction profiles into SDM for ICDs (Aim 3).This proposal is led by an Early Stage Investigator whose expertise in cardiac electrophysiology, geriatric medicine, and outcomes research will be complemented by an experienced research team with a strong record of collaboration. IMPACT: As the first comprehensive, prospective study of older ICD patients, TRACER-ICD will generate unique patient-centered and personalized data essential for characterizing outcomes of this common procedure in a vulnerable population. Much like other large cohort studies in older persons, we anticipate the robust data emerging from TRACER-ICD will serve as a rich resource that will improve care for millions of patients considering ICD implantation, and provide essential, evidence-based guidance for translating personalized outcome profiling into the SDM experience.