What Is Cardiac Arrest?

Cardiac arrest happens when the heart suddenly stops pumping blood to the body in a person who may or may not have been diagnosed with heart disease. It can come on suddenly or with other symptoms. Cardiac arrest is a life-threatening emergency. Calling 911, starting CPR and using an AED as soon as possible can increase the chance of survival.

More than 350,000 out of hospital cardiac arrest deaths occur each year in the U.S.

What are the symptoms of cardiac arrest?

Sudden loss of responsiveness and no normal breathing are signs of cardiac arrest.

A person may be in cardiac arrest if they:

• Suddenly collapse
• Lose consciousness (pass out)
• Stop breathing or are gasping for air
• Do not respond to shouting or shaking

If you think someone is in cardiac arrest, call 911 and start CPR right away. Learn more about what to do if someone is in cardiac arrest.

Is a heart attack the same as cardiac arrest?

No. The term heart attack is often mistakenly used to describe cardiac arrest. While a heart attack may lead to a cardiac arrest, they aren't the same.

Heart attacks are caused by a blockage that stops blood flow to the heart. A heart attack refers to death of heart muscle tissue due to the loss of blood supply. It’s a circulation problem. A heart attack is serious and sometimes fatal.

Cardiac arrest is caused when the heart’s electrical system malfunctions. This causes the heart to stop beating properly. The heart’s pumping function is arrested, or stopped.

Cardiac arrest is often fatal, but quick action can help save a life. Immediate CPR and rapid use of an AED can improve the chance of survival by helping restore a normal heart rhythm in some people.

Cardiac arrest may be caused by irregular heart rhythms called arrhythmias. A common arrhythmia associated with cardiac arrest is ventricular fibrillation. In ventricular fibrillation, the heart’s lower chambers suddenly start beating chaotically and don’t pump blood.

Learn more about the differences between cardiac arrest and heart attack.

View our Cardiac Arrest vs. Heart Attack infographic.

Is respiratory arrest the same as cardiac arrest?

No. Respiratory arrest is when a person stops breathing. Cardiac arrest can happen soon after if breathing is not restored quickly.

Respiratory arrest is a common cause of cardiac arrest in infants and children.

Respiratory arrest can be caused by:

• A blocked airway caused by choking, drowning, injury or a tumor
• Reduced breathing effort due to conditions such as:
  • Stroke
  • Spinal cord injury
  • Obesity
  • Metabolic disorder
• Weak breathing muscles caused by fatigue, disease or certain medications

Respiratory arrest and cardiac arrest are different conditions. But, without treatment, respiratory arrest can lead to cardiac arrest.

If someone is unresponsive and not breathing normally, call 911, begin CPR and use an AED if one is available.

Learn about CPR with rescue breaths after drowning and what to do if someone is choking.