I have witnessed a lot of cardiac arrests as a nurse. The patient usually becomes grey and clammy, not necessarily complaining about chest pain. The heart stops and they collapse. They need intensive CPR and usually defibrillation. Unfortunately if an arrest isnt witnessed and dealt with immediately the majority of patients dont survive. Cardiac arrest is not aheart attack. Heart attack is a shortage of oxygen to the heart due to blockage which expresses itself in severe crushing chest pain radiating down the left arm and also into the jaw line. the heart doesnt stop working. Cardiac arrest is where the heart stops completely and has to be rescusitated back to into cardiac rhythm. There is no cardiac output or rhythm during arrest