Signs of cardiac arrest: It strikes suddenly and without warning.

• Sudden loss of responsiveness (no response to tapping on shoulders)
• No normal breathing (the victim does not take a normal breath when you tilt the head up and check for at least five seconds) 

If these signs of cardiac arrest are present:

1. Call 9-1-1 for emergency medical services.
2. Get an automated external defibrillator (AED) (if one is available).
3. Begin CPR immediately and continue until professional emergency medical services arrive.
4. Use the AED as soon as it arrives.

If two people are available to help, one should begin CPR immediately while the other calls 9-1-1 and finds an AED.

Cardiac arrest is reversible in most victims if it's treated within a few minutes. This first became clear in the early 1960s with the development of coronary care units. Electrical devices that shocked the heart were discovered to turn an abnormally rapid rhythm into a normal one. Before then, heart attack victims had a 30 percent chance of dying if they got to the hospital alive; 50 percent of these deaths were due to cardiac arrest. In-hospital survival after cardiac arrest in heart attack patients improved dramatically when the DC defibrillator and bedside monitoring were developed. Later, it also became clear that cardiac arrest could be reversed outside a hospital by properly staffed emergency rescue teams trained to give CPR and defibrillate.

Immediate treatment is essential to survival of cardiac arrest. The problem isn't whether cardiac arrest can be reversed but reaching the victim in time to do so. The American Heart Association supports implementing a "chain of survival" to rescue people who suffer cardiac arrest. The chain consists of:

• Early recognition of the emergency and activation of the emergency medical services (EMS).
• Early defibrillation when indicated.
• Early bystander CPR (cardiopulmonary resuscitation).
• Early advanced life support followed by postresuscitation care delivered by healthcare providers

Learn more about the "chain of survival"

This content is reviewed regularly. Last updated 07/02/09.