A US man has become the first person in the world to get a heart transplant from a genetically-modified pig. David Bennett, 57, is doing well three days after the experimental seven-hour procedure in Baltimore, doctors say. The transplant was considered the last hope of saving Mr Bennett's life, though it is not yet clear what his long-term chances of survival are. "It was either die or do this transplant," Mr Bennett explained a day before the surgery. "I know it's a shot in the dark, but it's my last choice," he said. Doctors at the University of Maryland Medical Center were granted a special dispensation by the US medical regulator to carry out the procedure, on the basis that Mr Bennett - who has terminal heart disease - would otherwise have died. He had been deemed ineligible for a human transplant, a decision that is often taken by doctors when the patient is in very poor health. The pig used in the transplant had been genetically modified to kno