Unlike commercial health insurance, Medicare is a government program that guarantees benefits to covered beneficiaries on a fee-for-service basis when medically necessary services are provided by contracted providers. When it has been established that a patient has a heart condition, the care and treatment required to monitor or improve that condition are covered under the provisions of federal law, administered by the Centers for Medicare and Medicaid Services (CMS). Patients are required to pay out-of-pocket for a set percentage of covered services unless they also have a Medicare supplement plan.