Cardiac surgery involves surgery on the heart or heart valves. A cardiac surgeon performs heart surgery, also known as coronary artery bypass surgery, on patients who have heart disease or heart valve disorders. Reasons that may make heart surgery necessary are: coronary artery disease, congenital heart defects, disease of the heart valves, or heart attack. Some heart conditions can cause permanent damage to the heart muscle, and can be fatal.

Doctor density varies by specialty and location. The United States has 66 practicing cardiac surgeons. Broken out by state, cardiac surgery doctor density in Alabama is 2, in Arizona is 2, in California is 17, in Colorado is 1, in District of Columbia is 1, in Florida is 11, in Georgia is 3, in Illinois is 5, in Indiana is 1, in Iowa is 1, in Kentucky is 3, in Louisiana is 1, in Massachusetts is 1, in Michigan is 1, in Minnesota is 1, in Missouri is 6, in Montana is 2, in Nebraska is 1, in New Jersey is 1, in New York is 3, in North Dakota is 1, in Ohio is 4, in Oklahoma is 1, in Pennsylvania is 7, in South Carolina is 4, in Tennessee is 1, in Texas is 10, in Utah is 2, in Virginia is 1, in West Virginia is 4, and in Wisconsin is 1.