Could someone really come back from the dead? To some extent, it depends on what you mean by death. Sure, people can be revived through medical intervention (although that's not as common as TV medical dramas make us think), but sometimes things get a little more mysterious than that.
In something called the Lazarus Phenomenon, people actually wake from apparent death — after resuscitation attempts have been stopped.
Top image: Star Trek III: The Search for Spock.
Throughout our lives we find out, with ever-increasing bitterness, that life is not like television. On TV, all anyone has to do is strike a recently dead person firmly on the chest, breathe into their mouths, and scream, "Live, damn you," and the corpse will pop back to life before the next commercial break. In real life, CPR is effective at best thirty percent of the time — and sometimes has a success rate as low as two percent.
Sometimes, though, life goes fiction one better, and makes people seemingly spontaneously come back to life after the medical professionals have given up on resuscitation. This happens so often that it's the subject of speculation, and research, by medical professionals. It's called the Lazarus Phenomenon. Presumably because it can't be called "Aaaaaa! Zombies!"
The phenomenon gets its name from Lazarus, the Biblical figure resurrected by Jesus Christ. Lazarus lay dead for four days before he was called back to life. Most people who manifest this phenomenon come back to life less than ten minutes after resuscitation efforts are halted — with an average lag time of about seven to eight minutes. The most common cases that lead to the phenomenon are heart attacks, but it can happen to people in renal failure, people having breathing problems, hemorrhages, or drug overdoses. Almost anything that takes out the circulatory system is fair game.
Some cases that were classified as Lazarus didn't occur to people who were technically dead. These people simply didn't have heartbeats that approached, or were thought to regain, regular rhythm. All efforts to save them were put aside, doctors were resigned to the inevitable... and a few minutes later their heartbeat simply evened out and gained strength. That's not so dramatic. However, there have been at least 23 cases in which a person was in asystole, with no pulse and no electrical activity present in the heart, before their heart started up again.
A good example of this happened in the year 2000. A 66-year-old man, one of the few cases that includes a full report, was brought to an operating room with a leaking abdominal aortic aneurysm. He was given several medications and chest compressions, before being pronounced dead at 6:17 by both the surgeon working on him and the anesthesiologist. His medications were discontinued and any monitors attached to him were stopped. At 6:27, as the surgeon was lecturing medical students about the case, the surgeon noticed that suddenly the man had a pulse again. A team of doctors went to work and he came back to life.
The phenomenon, even when viewed through the most rosy of lenses, isn't an unqualified miracle. Only about 45 to 55 percent of Lazari maintain a high level of neurological activity. The rest sustain brain damage from either their injuries or a lack of circulation during the time they were "dead." Researchers, notorious for taking a glass-half-empty view of things, believe that the phenomenon either the result of delayed reaction to drugs or treatment, equipment failure, or the body temporarily reacting in such a way that it masks its signals and keeps them from being picked up by machines and doctors. People with breathing or airway problems, for example, can hyper-inflate their lungs, which causes major drops in blood pressure and cardiac rate. Researchers recommend, therefore, keeping seemingly dead bodies on machines in order to make sure no doctor misses any new Lazarus that comes along. (One patient actually started breathing again in the morgue.)
The news isn't all bad, though. It's thought that this phenomenon is, if anything, under-reported. More people are coming back than we think. Whatever is causing the phenomenon, it's interesting that people might, for some reason, come back from the seeming dead unaided. Then again, maybe it's more unnerving than interesting. None of them have come back with a taste for human flesh yet, but it's only a matter of time.