PROJECT SUMMARY / ABSTRACT Cardiac rehabilitation (CR) is widely recognized as an effective and life-prolonging treatment for cardiovascular disease (CVD), yet many patients do not benefit from treatment. More than half of patients who begin, ultimately dropout. Even among treatment adherent patients, one third are “non-responders”, and past investigations into the demographic and biological profiles of responders and non-responders have been unable to identify reliable differences that can explain why. Prior research on treatment adherence and responsiveness in CR has been limited by reliance on methodological approaches that only allow for a small number of assessments taken in medical environments that have limited generalizability to actual experiences during normal daily life. Building on the large body of research indicating that cardiovascular events and psychosocial distress share a common epidemiology, and by emerging evidence that transdiagnostic psychosocial processes (e.g., emotion regulation, daily behaviors and social interactions) are predictive of key cardiovascular outcomes, the present study employs a novel assessment approach to collect data from patients enrolled in CR as they go about their normal daily lives. N = 50 patients who are enrolling in a typical 12-week cardiac rehabilitation program will undergo two weeks of daily life assessments (the first during week 1 and the second during week 12 of the program). Assessments will include: 1) Ecological Momentary Assessment (EMA) for the collection of subjective data about patients’ cognitive and emotion regulation strategies in daily life, 2) behavioral observation using the Electronically Activated Recorder (EAR) for passive assessment of patients’ daily behaviors and social interactions, and 3) an Actiwatch, for passive assessment of accelerometry, heartrate and heartrate variability during daily life. Participant burden is minimal due to the use of passive assessment approaches. We will use advanced longitudinal, person-centered modeling approaches to identify specific, treatment-modifiable factors that affect treatment adherence and response to CR. We hypothesize that cognitive and emotion regulation strategies (Aim 1), daily activity pacing and social interactions (Aim 2), and patterns in continuously assessed cardiovascular biomarkers (Aim 3, Exploratory) will each predict treatment adherence and responsiveness outcomes. The study is innovative in that it is the first study to integrate these three cutting-edge methods, and is among the very first to apply “high resolution” daily life research approaches to improving treatment outcomes for patients with CVD. Results will be used as pilot data to inform a K or R application focused on developing and testing a precision-medicine informed intervention that further leverages ambulatory technologies such as mobile adaptive interventions to increase patient responsiveness to CR through daily life treatment targets identified ...