This study, Biobehavioral Intervention to Reduce PTSD Symptoms After an ICD Shock, addresses a critical need in cardiology care by describing the feasibility and acceptability of a timely, highly promising, electronically-delivered intervention for patients who have recently received an ICD delivered shock. The study intervention and outcomes are designed to reduce anxiety, enhance return to activities of daily living (ADLs), and prevent the development of severe distress and post-traumatic stress disorder (PTSD), and ultimately promote quality of life. The study is a two-arm, embedded mixed methods, randomized trial (N=60, 30/group). The purpose is to determine feasibility and potential effects of a self-management intervention (SPSM) plus usual care (UC) compared to UC alone, delivered during the critical 1 month period after an ICD shock when distress is high. The intervention will be delivered over 1 month following an ICD shock; a 6-month follow-up will be used to assess the sustainability of intervention effects and determine if the incidence of PTSD is reduced. SPSM includes: 1) training in heart rate (HR) self-monitoring; and 2) individualized learning through 4 self-paced, web-based modules. The study interventions are delivered at a crucial time, closely after an ICD shock when stress is high, but PTSD has not yet developed. The specific aims are to: 1) examine the effects of the SPSM intervention plus UC vs. UC alone on the primary outcome of ICD shock anxiety at 1 and 6 months post-shock event, 2) describe the impact of SPSM plus UC compared to UC alone on the secondary outcomes of total daily physical activity, depression, PTSD symptoms, QOL, salivary cortisol levels, and self-efficacy and outcome expectations at 1 and 6 months post-shock event, and 3) assess feasibility, acceptability, and safety of the SPSM intervention, SDOH will be used to describe differential responses to the SPSM intervention. This study fills a significant gap in the care of patients with an ICD, through the systematic testing of a brief, novel and cost-effective intervention that provides the knowledge and skills to improve quality of life. Study findings will be used to design future larger RCTs to test intervention effectiveness for more diverse samples and settings.