Booggie
Ripping out the heart and head would kill them, but as originals it is nearly impossible to do so to those unique vampires. Elijah planned on ripping out Klaus heart after he was weakened to kill him. It would take a vastly stronger being to do that kind of damage to them, and that kind of being just didn’t really exist in the universe that was shown. Don’t let them regrow head or heart, just make it difficult to almost impossible to remove them.