Each year, more than 2 million Americans have a heart attack or stroke, and more than 800,000 of them die; cardiovascular disease is the leading cause of death in the United States and the largest cause of lower life expectancy among blacks. Related medical costs and productivity losses approach $450 billion annually, and inflation-adjusted direct medical costs are projected to triple over the next two decades if present trends continue.(1) To reduce this burden, the Department of Health and Human Services (DHHS), other federal, state, and local government agencies, and a broad range of private-sector partners are today launching a . . .