They were trying to grow some body parts in vitro from stem cells but maybe a heart is too complex for that. It does serve a simple function but I guess reliabilty issues would rule out anything artifical.
My Dad had a Pacemaker fitted when he was about 60 years of age due to angina , every so often he would go to hospital to have it checked and how the tiny battery was doing , he called it his service and MoT akin to adjusting his tick over on his car.
Yes after all the heart is a muscle powered means of pumping blood and oxygen around the body for years and years all being well, perhaps one day they maybe able to replicate it and be able to service it or replace it quickly when needed
