Cardiac arrest

Man gets chest painA cardiac arrest happens when your heart stops pumping blood around the body.

If you have a cardiac arrest, you lose consciousness almost at once.

There are also no other signs of life such as breathing or movement.

This is an emergency and if you witness a cardiac arrest you should call 999 immediately.

What is the difference between a heart attack and cardiac arrest?

A cardiac arrest is different from a heart attack.

  • Most heart attacks are caused by coronary heart disease.
  • If you have a heart attack, it does not always lead to a cardiac arrest.
  • A cardiac arrest does not always happen because you have a heart condition.

If you witness a cardiac arrest, you can increase the person’s chances of survival by phoning 999 and giving immediate CPR.

Cardiopulmonary resuscitation (CPR)

Cardiopulmonary resuscitationUnless someone starts cardiopulmonary resuscitation (CPR) the person may suffer permanent damage to the brain and other organs.

CPR means:

  • chest compression (pumping the heart by external cardiac massage), to keep the circulation going until the ambulance arrives and
  • rescue breathing (inflating the lungs by using mouth-to-mouth resuscitation),

Ambulance staff are trained in advanced resuscitation and all emergency ambulances carry a defibrillator.

Learn life-saving skills such as hands-only CPR or sign up to a Heartstart course.

What causes a cardiac arrest?

DefibrillatorThe most common cause of a cardiac arrest is a life threatening abnormal heart rhythm called ventricular fibrillation (VF).

Ventricular fibrillation occurs when the electrical activity of the heart becomes so chaotic that the heart stops pumping and quivers or 'fibrillates' instead. There are various causes of VF. These include heart-related problems, such as:

VF can also happen if: 

  • there is a lack of oxygen in your body - for example, if you are choking
  • you are electrocuted
  • you have used recreational drugs, such as cocaine or methadrone 
  • you lose a large amount of blood

VF can sometimes be corrected by giving an electric shock through the chest wall, using a device called a defibrillator.

Our scientists are fighting for every heartbeat

Your donations fund the life-saving work of our researchers in their search for a cure for heart failure. Find out more about our Mending broken hearts appeal.