Lazarus syndrome

Lazarus syndrome or autoresuscitation after failed cardiopulmonary resuscitation[1] is the spontaneous return of circulation after failed attempts at resuscitation.[2] Its occurrence has been noted in medical literature at least 25 times since 1982.[3] Also called Lazarus phenomenon, it takes its name from Lazarus who, in the New Testament account, was raised from the dead by Jesus.[4] The syndrome name is ironic in that it incorporates an example of the scientifically rejected concept of resurrection into a scientifically documented medical phenomenon.

Occurrences of the syndrome are rare and the causes are not well understood. One theory for the phenomenon is that a chief factor (though not the only one) is the buildup of pressure in the chest as a result of cardiopulmonary resuscitation (CPR). The relaxation of pressure after resuscitation efforts have ended is thought to allow the heart to expand, triggering the heart's electrical impulses and restarting the heartbeat.[2] Other possible factors are hyperkalemia or high doses of epinephrine.
http://en.wikipedia.org/wiki/Lazarus_syndrome