A 25-year-old Michigan man has finally received a heart transplant after living for more than a year without a heart inside him at all.

Stan Larkin lived for more than 555 days with an artificial heart strapped to his back in a backpack.

The device did all the things his heart once did when it was healthy: pumping oxygen-rich blood around his body and keeping him alive. But Larkin says the device wasn’t easy to get used to at first.

“It was kind of stressful at the beginning, because I had to get used to the noise, It was a lot of noise 24/7, the heartbeat,” he told CTV News Channel from the University of Michigan Hospital Thursday.

“As I got used to the noise, I could finally go to sleep. After that, I had to get used to carrying three extra bags with me, everywhere I went. I had to have all this stuff every time I moved.”

Larkin suffered from right ventricular dysplasia, a heart condition in which the muscle of the heart’s right ventricle develops tough, fibrous tissue so that the ventricle will no longer contract properly. The condition severely hampers the heart’s ability to pump blood and puts patients at high risk of sudden cardiac arrest or death.

It’s not known what causes the condition, but it can run in families. In fact, Larkin’s younger brother Dominique had the same condition before he too underwent a heart transplant.

In late 2014, Larkin’s condition suddenly worsened, sending him into cardiogenic shock and leading doctors to decide to remove his heart entirely.

At first, doctors hooked him up to an artificial heart machine dubbed “Big Blue.” The washing machine device weighed more than 188 kg (400 pounds), which meant that Larkin would not have been able to leave the hospital until doctors found a matching donor heart – a process that could take months, or even years.

So Larkin agreed to become the first patient in Michigan to be fitted with a new, portable device known as a SynCardia Freedom Total Artificial Heart.

The device pushes compressed air through long tubes that enter Larkin’s chest, pumping blood through his body.

Larkin says the device made him feel so much better but he admits there were still limitations on what he could do, including bathing.

“Because it was electric, I couldn’t get in the shower. I had to pretty much wash up in the bath,” he said.

Eighteen months after having the Syncardia machine hooked up, a suitable donor heart was finally found for Larkin, which was transplanted into him one month ago. He’s back in hospital this week for his one-month checkup but says he’s feeling great.

He hopes others with severe heart disease will be able to have the device implanted too.

“I would recommend it because if your other organs are sick, it will bring them back and get them 100 per cent healthy and ready for transplant,” he said.