RecruitingBehavioural interventionHome-Based Exercise Program Using Mobile Technology After Left Ventricular Assist Device ImplantationThe goal of this clinical trial is to evaluate the effects of a home-based exercise program using mobile technology on physical activity and capacity, frailty and muscle mass, and quality of life in patients with a newly implanted HeartMate 3 left ventricular assist device (HM3 LVAD). Researchers will compare the effects of an exercise intervention vs. usual care on physical activity and capacity, frailty and muscle mass, and quality of life.