“Cardiac Arrest is the sudden, abrupt loss of heart function.  The victim may or may not have diagnosed heart disease.  It’s also called sudden cardiac arrest or unexpected cardiac arrest.  Sudden death (also called sudden cardiac death) occurs within minutes after symptoms appear.

The most common underlying reason for patients to die suddenly from cardiac arrest is coronary heart disease.  Most cardiac arrests that lead to sudden death occur when the electrical impulses in the diseased heart become rapid (ventricular tachycardia) or chaotic (ventricular fibrillation) or both.  This irregular heart rhythm (arrhythmia) causes the heart to suddenly stop beating.

 Some cardiac arrests are due to extreme slowing of the heart.  This is called bradycardia.

Other factors besides heart disease and heart attack can cause cardiac arrest.  They include respiratory arrest, electrocution, drowning, choking and trauma.  Cardiac arrest can also occur without any known cause." 

-American Heart Association:
www.americanheart.org/presenter.jhtml?identifier=448

Unconscious, Unresponsive and Stops Breathing Normally:
A victim in sudden cardiac arrest becomes unconscious, unresponsive and stops breathing normally.  This is due to the lack of blood flow resulting from the chaotic heart rhythm.  In this situation implement the American Heart Association’s “Chain of Survival.”

Agonal Breathing:
“In the first few minutes after sudden cardiac arrest, a victim may only gasp. Gasping is not breathing.” 
-American Heart Association HeartSaver AED Student Workbook Page 10

Convulsions or Seizures:
Eyewitness accounts of a sudden cardiac arrest sometimes include the victim experiencing seizure or convulsion activity.  These reactions may occur as part of the brain’s reaction to the lack of oxygen.  If these symptoms accompany unconsciousness, unresponsive and no breathing or abnormal breathing, implement the American Heart Association’s “Chain of Survival."