Hannah Clark is no ordinary teenager and her normal life today could not have been possible without a unique, life-changing heart surgery. In 1994 when she was eight-months-old, Hannah was diagnosed with cardiomyopathy -- an inflammation of the heart muscle that impairs the heart's ability to work properly. Hannah's heart was failing and she needed a transplant. But instead of taking her own heart out, doctors added a new donated heart to her own when she was just two-years-old. The so-called "piggyback" operation allowed the donor heart to do the work while Hannah's heart rested. Then in February 2006, her doctors tried something that had never been done before: They took out the donor heart. Three years later, Hannah has no need for any drugs and has been given a clean bill of health. The operation was a success. - CNN.com