Understanding Baseline Physical Activity in Cardiac Rehabilitation Enrollees Using Mobile Health Technologies

Baseline physical activity in patients when they initiate cardiac rehabilitation is poorly understood. We used mobile health technology to understand baseline physical activity of patients initiating cardiac rehabilitation within a clinical trial to potentially inform personalized care. The VALENTINE (Virtual Application-Supported Environment to Increase Exercise During Cardiac Rehabilitation Study) is a prospective, randomized-controlled, remotely administered trial designed to evaluate a mobile health intervention to supplement cardiac rehabilitation for low- and moderate-risk patients. All participants receive a smartwatch and usual care. Baseline physical activity was assessed remotely after enrollment and included (1) 6-minute walk distance, (2) daily step count, and (3) daily exercise minutes, both over 7 days and for compliant days, defined by 8 hours of watch wear time. Multivariable linear regression identified patient-level features associated with these 3 measures of baseline physical activity. From October 2020 to March 2022, 220 participants enrolled in the study. Participants are mostly White (184 [83.6%]); 67 (30.5%) are female and 84 (38.2%) are 65 years old. Most participants enrolled in cardiac rehabilitation after percutaneous coronary intervention (105 [47.7%]) or coronary artery bypass surgery (39 [17.7 %]). Clinical diagnoses include coronary artery disease (78.6%), heart failure (17.3%), and valve repair or replacement (26.4%). Baseline mean 6-minute walk distance was 489.6 (SD, 143.4) meters, daily step count was 6845 (SD, 3353), and exercise minutes was 37.5 (SD, 33.5). In a multivariable model, 6-minute walk distance was significantly associated with age and sex, but not cardiac rehabilitation indication. Sex but not age or cardiac rehabilitation indication was significantly associated with daily step count and exercise minutes. Baseline physical activity varies substantially in low- and moderate-risk patients enrolled in cardiac rehabilitation. Future studies are warranted to explore whether personalizing cardiac rehabilitation programs using mobile health technologies could optimize recovery. URL: https://www. gov; Unique identifier: NCT04587882.