Although many operations using cardiopulmonary bypass today do not require a cardiac chamber to actually be opened (such as coronary artery bypass surgery in adults), we use the terms "open-" or "closed-" heart surgery to describe whether a procedure uses the heart-lung bypass machine support.

The terms "open-heart surgery" and "closed-heart surgery" date from the early days of cardiac surgery (the 1940s and 1950s). The earliest cardiac operations were all for congenital heart disorders, and heart-lung bypass machine support was required to allow surgeons to open the heart to work on its internal deformities.

Closed-heart surgery does not use the cardiopulmonary bypass machine.