It has become known as a "heart in a box"...
And it's helping Zack Poe of Kentucky live.
The 20-year-old is the state's first patient to receive the SynCardia Total Artificial Heart.
A day after his surgery, Zack was off a breathing tube and a few days later he was out walking around.
Doctors say Zack's recovery is remarkable and he agrees.
I feel a million times better because of the outflow volume ...I've been able to walk longer without pain than I have in months, and I think the larger thing, even without having the pain, is that people who have to wait for transplants and don't have the opportunity to necessarily live until that transplant happens, they have months and years now they can wait.
Zack still needs a new heart.
He's on a waiting list for a heart donation.
Zack's dad is encouraging people to become organ donors, so they can save the lives of people like his son.