Open heart surgery refers to a type of surgical procedure where the chest is opened and surgery is performed on the heart, its surrounding tissues or blood vessels. This term usually implies that the surgeon has accessed the patient's heart by splitting the breastbone (sternum) and temporarily stopping the heart so that it can be operated upon. Open-heart surgery is typically used to treat severe conditions such as coronary artery disease, valvular heart disease or congenital heart defects. The procedure may involve replacing or repairing a damaged heart valve, bypassing blocked blood vessels in the heart, or even transplanting a new heart into the patient's chest. Open-heart surgery is a major operation that requires general anaesthesia and typically involves a hospital stay of several days to weeks for recovery.