Section 8G. Any contract, except contracts providing supplemental coverage to medicare or other governmental programs, between a subscriber and the corporation under an individual or group hospital service plan which shall be delivered or issued or renewed in the commonwealth shall provide, as a basic benefit to all individual subscribers and members within the commonwealth and to all group members having a principal place of employment within the commonwealth, for expense for cardiac rehabilitation. Cardiac rehabilitation shall mean multidisciplinary, medically necessary treatment of persons with documented cardiovascular disease, which shall be provided in either a hospital or other setting and which shall meet standards promulgated by the commissioner of public health after reviewing proposals submitted by the Massachusetts Society for Cardiac Rehabilitation, Inc. and after notice and public hearing on the proposed standards. Such standards shall include, but not be limited to, outpatient treatment which is to be initiated within twenty-six weeks after the diagnosis of such disease.