He lived 555 days without a heart

 Stan Larkin lived more than a year(555 days)without a heart.He wore,an 'artificial heart' in a backpack 24/7 for 555 days which pumps blood around his body and kept him alive.

                              Syncardia is the temporary artificial heart that replaced his failing heart in the chest,including its chambers and four valves.He received a full heart transplant after getting a donor.