A 12-year-old girl, Hannah Clark, is believed to be the first patient in the world who had her heart "doubled" through a complex procedure - transplant, and then removed after 10 years, leaving the initial heart in a perfect state. Hannah Clark, from south Wales, previously suffered from cardiomyopathy, a serious disease of the heart muscle, which causes the organ to expand in size in order to try to compensate for the fact that its ability to pump blood is compromised. Hannah's heart was double in size by the age of 2, doctors fearing that it will stop functioning. Medics at Harefield Hospital, Middlesex, decided 10 years ago that the girl needs a new heart, so they transplanted another one. The new organ was placed in the right part of her chest and attached to her original heart, which remained in its original position. The organ pumped most of the blood in her body, while the other organ pumped a small quantity, being able to rest since the new heart took the most important task. The aortas, the major blood vessels which leave the heart, were merged to supply blood in an effective way all over the body, the circulation of the normal heart remaining unchanged. For 10 years, the new heart took all the major tasks and the doctors believe it is time that Hannah's heart should be put again to work. The surgery went well and took shorter than expected, 4 hours instead of 8. Having only her heart, the girl made such a good recovery and returned home in only 5 days. Medical experts said this procedure represents an important step in treating people suffering from cardiomyopathy, with inflamed hearts which functions poorly.