A cardiac arrest is when your heart suddenly stops pumping blood round your body, commonly because of a problem with electrical signals in your heart.

When your heart stops pumping blood, your brain is starved of oxygen. This causes you to fall unconscious and stop breathing. 

What are the signs of a cardiac arrest?

There are usually no symptoms before a cardiac arrest and, without immediate treatment, it will be fatal. If someone is in cardiac arrest:

• they won’t be conscious
• they won’t be responsive
• they won’t be breathing, or breathing normally.

A cardiac arrest is a medical emergency. If you witness a cardiac arrest, you can increase the person’s chances of survival by phoning 999 immediately and giving CPR.