The 57-year-old is said to be breathing by himself.
A dying man in the US has become the first in the world to receive a pig's heart in a transplant.
57-year-old David Bennett is said to be breathing by himself - three days after receiving the genetically-modified organ during an operation in Maryland.
It's too soon to know if it'll work long-term, but his surgeon Professor Bartley Griffith says it's a lifeline: