The most common cause of cardiac arrest is ventricular fibrillation, where the bottom chamber of the heart beats so rapidly that nearly no blood is pumped to the rest of the body. Cardiac arrest can also be caused when the heart does not respond to electrical impulse or the heart rate becomes slows or stops.
The first sign of cardiac arrest is a loss of pulse leading to loss of consciousness. The heart will stop beating and there will loss of blood flow to other organs, which causes death within minutes. Preceding warning signs may include chest pain, shortness of breath, dizziness or lightheadedness.
Sudden cardiac death is diagnosed someone has loss of consciousness and no pulse or electrical signal can be detected.
Cardiac arrest is a medical emergency that warrants immediate attention with an automated external defibrillator (AED). This device shocks the heart and restores a normal rhythm.