See below. Patients who have had a heart attack, angioplasty & stent, bypass surgery, and valve replacement are candidates for cardiac rehab. Also patients with angina pectoris (chest pain) who are treated with medical therapy would benefit from rehab.
Cardiac rehab. Technically "cardiac" patients: after heart attack, stent, bypass surgery, poor heart muscle (cardiomyopathy). In a more general sense, cardiac rehab can improve everybody's functional capacity and wellbeing.