Did you know a man once lived for 555 days without a heart in his chest, and spent much of that time playing sports with his friends?

His name was Stan Larkin. He was kept alive by an artificial heart strapped to his back for 555 days while he waited for a transplant, a case that amazed the medical world. Doctors at the University of Michigan had installed a temporary total artificial heart, the SyncArdia device, to keep his blood moving until a donor could be found.

The device did the work of both lower chambers of the heart, and it didn’t sit inside him like a pacemaker. It was connected to a driver unit that weighed about 13 pounds. This is why reports described him carrying his “heart” around in a backpack.

The long wait is not what made his case remarkable. Patients had lived for long periods on artificial hearts before, but Larkin became the first patient in Michigan to go home with the portable device. Such patients usually have to stay in hospital for the whole wait. Larkin lived at home and kept up an ordinary life as far as he could, and he even played sports with his friends during that time.

His wait ended after those 555 days, when he finally received the heart transplant he needed after about 18 months without a heart.

Larkin’s story shows how far medicine has moved beyond treating a failing heart as a hospital-bed emergency. A machine can now keep a person alive, mobile and active for more than a year, long enough for the right donor to come along.