The illness was wasting his muscles away and prevented him from receiving a heart transplant, causing doctors in Rome to insert the 4cm long electrically activated hydraulic pump "heart" in his left ventricle. A plug behind his left ear and a battery attached to his belt powers the heart, which will gift him another 20-25 years of life that he wouldn't have had without this operation.
If you compare the unnamed boy's 90g heart with the first ever artificial heart from 1969, you can see just how far the medical world has progressed in those 41 years. The photo above shows the first ever artificial heart, which was placed inside a man's heart for 64 hours while he waited for a donor heart. [Telegraph and Daily Mail]