Hybrid cardiac rehabilitation - The state of the science and the way forward

Cardiac rehabilitation (CR) improves exercise capacity and health-related quality of life (HRQoL) in a broad range of patients, including those with coronary artery disease, heart failure (HF), after heart valve surgery, and after heart transplantation. Unfortunately, in traditional center-based CR programs participation and adherence are low. A hybrid model of CR, combining center-based and home-based CR services, has been proposed and is currently being studied as a potential way to help bridge the participation gap, while maintaining the beneficial patient outcomes from CR. However, the ideal composition of a hybrid CR program has not been universally agreed upon. In the present review, we define hybrid CR as any combination of supervised center-based and monitored home-based exercise, where at least two of the core components of CR are addressed. Using this definition, we searched for studies comparing hybrid CR with: (1) traditional center-based CR among CAD patients, (2) usual care among CAD patients, and (3) usual care among HF patients. We found nine studies which fit both our definition and comparison groups. The structure of the hybrid CR programs differed for each study, but typically began with a center-based component lasting 2-11 weeks and transitioned to a home-based component lasting 10-22 weeks, with 3-5 exercise sessions per week composed of either walking (usually with a treadmill) or cycling for 25-35 min at 60-75% maximal heart rate. Patients recorded data from home exercise sessions, via either a digital heart rate monitor or accelerometer, into logbooks which were reviewed by a therapist at specified intervals (often via telephone). Counseling on risk factor management was predominantly provided during the center-based component. In these studies, hybrid CR led to similar short-term outcomes compared to traditional CR in patients with coronary artery disease (CAD), as well as increased adherence and reduced delivery costs. Compared with usual care, in patients with CAD, hybrid CR reduced cardiovascular events, and improved lipid profiles, exercise capacity, and HRQoL. In patients with HF, compared with usual care, hybrid CR improved physical function, exercise capacity, and HRQoL. Ongoing studies may clarify the combination of center-based and home-based CR which produces superior outcomes, and may also better define the role that technology should play in CR interventions.