Lazarus syndrome, also known as 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 38 times since 1982.[3][4] It takes its name from Lazarus who, as described in the New Testament of The Bible, was raised from the dead by Jesus.[5] Occurrences of the syndrome are extremely rare and the causes are not well understood. One hypothesis 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.