A heart transplant is an operation in which a diseased, failing heart is replaced with a healthier donor heart. Heart transplant is a treatment that's usually reserved for people whose condition hasn't improved enough with medications or other surgeries.
Heart transplants are performed when other treatments for heart problems haven't worked, leading to heart failure. In adults, heart failure can be caused by: Coronary artery disease, Heart valve disease, Failure of a previous heart transplant etc.
In children, heart failure is most often caused by either a congenital heart defect or cardiomyopathy. Another organ transplant may be performed at the same time as a heart transplant (multiorgan transplant) in people with certain conditions at select medical centers.