Rather than fill the first few lines of this story with endless heart puns, we’ve decided to marvel at how a 25-year-old was able to live for 17 months without a heart.

Stan Larkin spent that time walking around with a backpack. Inside that pack was a lifesaving machine, powered by compressed air, that replaced the functions of a working heart as Larkin awaited a transplant donor to replace the defective heart that failed him.

With about 120,000 names on the organ transplant waiting list, devices like this can buy precious time.