Italian doctors are reporting that they kept a 16-month-old boy alive for 13 days as he waited for a heart transplant by implanting him with the world’s smallest artificial heart. The boy suffered from dilated myocardiopathy, in which the heart muscle stretches or enlarges, impairing function. The tiny titanium pump the boy received weighs only 11 grams, compared to artificial hearts for adults which weigh about 900-grams. The device was invented by American artificial heart pioneer Robert Jarvik and, because it had previously only been tested in animals, the procedure required special permission from Italian health authorities. The boy eventually received a heart transplant and is now doing well, according to his doctors.