The unnamed 19-year-old was shot by a colleague wielding a nail gun while working in a wooden pallet factory in Canuelas, Buenos Aires.
The man was taken to El Cruce Nestor Kirchner Hospital after the accident last Monday.
An x-ray revealed the nail had pierced straight through his heart muscle to become lodged in one of its chambers.
Only three people in the world have survived this type of injury, according to the hospital's CEO, Arnaldo Medina.
And this is the first time it has happened in Argentina, he added.