A man in the US has become the first in the world to receive a successful pig-to-human heart transplant.
David Bennett Sr. was previously told he was ineligible for a transplant, according to the Independent, however was offered the chance of having a non-human heart put in his body instead.
The 57-year-old from Maryland had been admitted to hospital weeks ago after suffering from a 'life-threatening' case of heart arrhythmia, which is when your ticker has an irregular heartbeat.
He was placed on a heart-lung bypass machine to keep him alive.
Mr Bennett had already received surgery that involved a pig valve being put into his heart, however physicians realised they needed something else to ensure the patient lived.
The Independent reports the team at University of Maryland Medical received emergency approval from the Food and Drug Administration to input the pig's heart into Mr Bennett's body.
Bennett said: "It was either die or do this transplant. I want to live. I know it's a shot in the dark, but it's my last choice. I look forward to getting out of bed after I recover."
They sourced the heart from a 108-kilogram standard, male pig.
Regenerative medicine company called Revivicor managed to genetically alter the pig's DNA by removing three genes that would have resulted in David's body rejecting the organ.
Revivicor then added six human genes into the pig's DNA to ensure the heart would be accepted.
The organ was transported to the hospital and David underwent surgery last Friday (7 January).
In the days since the operation, it appears the heart has been accepted by David's body.
Dr Bartley Griffith, the director of the cardiac transplant program at the medical center, told The New York Times: "It creates the pulse, it creates the pressure, it is his heart.
"It's working and it looks normal. We are thrilled, but we don't know what tomorrow will bring us. This has never been done before."
Known as 'xenotransplantation', this type of transplant surgery could well indeed change the game for the tens of thousands of people who are in desperate need of an organ.
Dr Griffith added in a statement: "This was a breakthrough surgery and brings us one step closer to solving the organ shortage crisis.
"There are simply not enough donor human hearts available to meet the long list of potential recipients."
Xenotransplants have been going on since the 1980s. A baby girl became the first infant to receive a baboon heart in 1984 to cure a fatal heart condition, however she died a month after the procedure.
The BBC reports a man received a pig kidney last year, and while the surgery was successful, he was brain dead and had no chances of recovering.
Stewart Perrie