Necromantic Surgery

As you can probably tell, I sit around and ponder the silliest uses of magic. Here’s one that occurred to me: Necromantic Surgery. What do I mean? Well, most games have some manner of necromancy - making dead things come to life again, well, unlife. In Legend Quest, a healer’s resuscitation will not work if the body is in a state that cannot sustain life. So you cannot resuscitate a body without a head or with a spear still sticking in the heart. You have to repair the damage and then bring life back to the body.
What if the reason the person died was more normal? What if they had a bad heart and it failed? I guess in some games, they would just resurrect the guy and everything would be alright, but that isn’t how I work it. Imagine this: A necromancer casts a spell similar to zombie on a heart inside someone’s chest. The zombie heart then starts beating as would have been considered “normal”. He then heals up the chest cavity and resuscitates the person. The guy with the bad ticker now has a zombie heart keeping him alive. There should be a risk of disease from the undead thing sitting inside his chest, but wards against disease are damn near common.
Truth be told, there are probably other ways to accomplish it - curing the diseases of the heart, “healing” the damage to the heart (something I always think is WAY too easy in fantasy games), something like that. But for a strictly “cool factor”, I love this idea. Maybe the guy is an evil warlord and none of the goody goody healer priests will do a cure on him, so he has to resort to the use of necromancy. Don’t get me started on alignments, because I hate those, but evil gods aren’t usually too quick with those healing spells.
There are more applications to this possibility, even undead “people” that function as lab equipment. Sure it’s gross, but this is HIGH fantasy right? Sometimes you need something way over the top or your players will just “been there/ done that”.