quick thought
how viable is it to use other animal hearts in the place of human hearts?
like say you put in an elephant heart to replace your own or something what would happen
Xenotransfusion is already a thing
As for animal hearts in place of human hearts, pig heart valves are used in heart surgery so its a start
pig blood i've also heard is being used for blood transfusions, first experiment was in the 1600's
Still has alot of technical strings attached, but atleast we have a start with it