Twelve-year-old Hannah Clark is believed to have become the first British patient to have her heart transplant reversed.
Hannah had a condition known as cardiomyopathy. This is a serious disease of the heart muscle, which causes the organ to expand in size to try to compensate for the fact that its ability to pump blood is compromised. Her heart had already doubled in size by the age of just two, and there were real fears it would soon give out completely.
Ten years ago, doctors at Harefield Hospital, Middlesex, decided to give Hannah a new heart. The new organ was inserted into the right side of the chest and attached to Hannah's original heart, which remained in position. The donor organ took over the job of pumping most of her blood around the body. The original heart still pumped some of Hannah's blood, but, with most of the pressure relieved by the new organ, was effectively able to rest. The two major blood vessels leaving each heart - the aortas - were merged, to ensure that a unified blood supply to the rest of the body. However, the circulation of the original heart was not fundamentally changed.
Hannah's donor heart worked fine until last November, when a routine check-up showed her body was beginning to reject it. Surgeons at London's Great Ormond Street Hospital operated to disconnect the donor heart, leaving Hannah's own heart to take on the sole role of pumping blood around the body. The surgery went smoothly. Although it was scheduled to take eight hours, it was completed in just four.
Hannah made such a good recovery that she was able to come home within five days. She no longer has to take powerful drugs to suppress her immune system.