Cardiac Arrest is asystole, which is absence of systole, failure of the ventricles of the heart to contract (usually caused by ventricular fibrillation), a person loses consciousness, has no pulse, no blood pressure.  The heart is not functioning at all.  When the heart has stopped beating and pumping blood to the organs the person is dying and without proper intervention including the correct choice of medications to aid with CPR, this person will surely die.  A person may still die when cardiac arrest has occurred, especially if reversible causes are not corrected.  It is important for licensed medical professionals to consider an ACLS course to stay up to date with appropriate interventions following the algorithms approved by the American Heart Association.