However, the victim can't be too dead. The question of survival begins with whether we're discussing clinical death or biological death.
First comes clinical death, when breathing and blood flow stop. Clinical death is the same as cardiac arrest: The heart has stopped. Technically, clinical death requires both the heart and the breathing to stop, but that's just semantics. Breathing will cease within a few seconds of the heart stopping.
Clinical death is reversible. There's a window of about 4 minutes from the moment of cardiac arrest to the development of serious brain damage. If blood flow can be restored -- either by CPR or by getting the heart pumping again -- the victim could come back from clinical death. It's not a sure thing; success rates for CPR are pretty dismal. In a 2010 Johns Hopkins study of victims suffering cardiac arrest somewhere other than a hospital, only 7% of cardiac arrest victims lived long enough to be discharged from the hospital. Those are not good odds for coming back from clinical death.
Biological death is brain death, and there's no turning back from brain death. That is irreversible death. Just to make things a bit more complicated, however, it is possible to keep the body alive while the brain is dead. The heart is more of a subcontractor than an employee of the body; it keeps its own hours and works without direct supervision by the brain. Since the heart works without brain input, it's possible to keep it going for a long time after the brain is dead. Indeed, that's one way organ donation happens.
There are physical signs of irreversible death that emergency medical responders use to decide whether to attempt CPR on a cardiac arrest victim. The hard truth is: Some people are just plain dead by the time they're found.
Weisfeldt ML, et al. "Survival after application of automatic external defibrillators before arrival of the emergency medical system: evaluation in the resuscitation outcomes consortium population of 21 million." J Am Coll Cardiol. 2010 Apr 20;55(16):1713-20.