I think it all depends on the circumstances, if you had intended to maliciously wound someone who would have survived if they accepted medical treatment you would be done for manslaughter, rather than attempted murder.
I wouldn't have a clue what the courts would decide if there wasn't intent and the cause of death was a relatively minor accident, say you knocked someone over in your car at 5mph, they broke their leg which resulted in a pierced artery but refused treatment I would find it very hard to find you of being guilty of anything.