Though people who need physical therapy are in contact with their PTs in the course of their physical rehabilitation rather than with their doctors, the fact is that one cannot undergo a course of rehabilitation procedure without a consult with a legitimate PM&R or rehab doctor.

A cardiac patient who underwent a coronary bypass will be likely referred by his cardiologist to a rehab doctor to get back into shape so to speak.
A patient who recovered from a stroke that affected his motor skill, would be referred by his neurologist to a rehab doctor gain back some of his lost mobility.

Cardiac rehabilitation is highly recommended for heart patients for them their quick recovery relating to not only their physical functions but also to their mental and social functions. The ultimate goal of a cardiac rehabilitation is to slowly and ultimately reverse the progression of the heart disease condition which could in turn reduce if not totally eliminate the risk of another cardiac attack or any related heart disease. Cardiac rehabilitation programs basically include:

Guidance and counseling for the patient to better understand and mange the disease
A set of exercise program
Basic counseling on nutrition and his prescribed medications
Help the heart patients to modify high risk factors e.g. high cholesterol level and high blood pressure; obesity; diabetes and smoking.
Give the patient the right information on his physical limitations and guide him to facilitate the patient to return to work, if applicable.
Stroke rehabilitation is more of a team effort since most stroke patients suffer brain injury too at different levels. A rehabilitation team normally consists of neurologists, physiatrists (rehab doctors), physical and occupational therapists, psychologists, speech and language pathologists and in some cases, cardiologists too.
A good medical rehabilitation team would have to address six major areas of concern:
The patients mobility relating to basics such as getting in and out of a bed, sitting up and sitting down
The patients locomotion movements such as walking, climbing stairs, using a walker or wheelchair maneuverability.
Basic self-care like self-grooming and hygiene, cooking and even driving a car.
Communication as stroke patients have speech problems, difficulty in swallowing and remembering suitable words
Cognitive functions and memory problems
Control of bladder and bowel movement

The primary team members are the physiatrist or rehab doctor and his team of physical, occupational and speech therapists. There are other medical cases where physical rehabilitation is needed e.g. carpal tunnel syndrome, cervical spondylosis, tendinitis, whiplash, sciatica, back pain, patella-femoral syndrome and other muscle, bone and nerve disorders.