A 12-year-old girl from South Wales is believed to have become the first heart transplant patient in the UK to have her donor organ removed and her own heart brought reinvigorated.

Hannah Clark, who has also suffered from cancer, had the operation, carried out on 20 February, after her body rejected her donor heart. The procedure is important as it shows that surgeons can allow a heart with acute inflammation to rest itself by using a "piggy back heart" before reconnecting their own organ. Previously, patients died or had transplants before their hearts had a chance to recover.

The heart specialist Sir Magdi Yacoub was persuaded to come out of retirement by Miss Clark's parents to reconnect the dormant heart he cut off 10 years ago.

Both operations have saved her life. Aged two, she had cardiomyopathy, which doubled the size of her heart and made it likely to give out. The replacement worked until November when a routine visit to a cardiologist revealed that her body was rejecting it.

She was told she could spend months in intensive care but was out within five days - all the more impressive considering she has been battling lymph cancer and successfully underwent chemotherapy in January.

She no longer needs to take strong anti-rejection drugs and hopes to take part in the Transplant Games later this year, competing in swimming, long jump and table tennis.