If so, would cryogenically freezing someone while they're still alive1 be permissible, since even though that involves heart etc. stoppage, it is intended to be reversible?
If mere intent is not enough, suppose reviving from freezing actually becomes possible in the future, with some chance X of success. Would that make freezing while alive permissible? Would it depend on how large X is?
1 Freezing someone while they're still alive may be needed when there's a degenerative disease, or some other situation that would make freezing after death too late to have any chance of reviving.