Cardiac arrest - What is it?

When someone has a cardiac arrest, their heart stops beating. This means blood doesn't get pumped around the body and oxygen doesn't reach the brain and other organs. If the heart stops beating for more than a few minutes, a person is unlikely to recover.

Cardiac arrest is a medical emergency that needs to be treated immediately. To understand what happens during a cardiac arrest, it helps to know a little bit about the heart. See How your heart works.

Before a cardiac arrest, the heart beats abnormally. Two things can happen.[1]

The heart beats fast (150 to 200 beats a minute) and the beats start in the lower chambers (ventricles) of the heart, instead of the upper chambers. Doctors call this pulseless ventricular tachycardia.
The heart beats very fast (more than 300 beats a minute) and very irregularly. The beats start in the ventricles, instead of the upper chambers. Doctors call this ventricular fibrillation.

If the heart beats like this, blood isn't pumped to the lungs, the rest of the body, and back to the heart. If no blood is coming back into the heart, it stops beating. This is a cardiac arrest.

You are more likely to have a cardiac arrest if you:[1]

Have heart disease
Have had a heart attack
Have heart failure
Are middle aged or older
Are a man.

References

Lang ES, Al Raisi M. Ventricular tachyarrhythmias (out of hospital cardiac arrests). Clinical Evidence. 2006; 15: 295-300.

Glossary

heart disease: You get heart disease when your heart isn't able to pump blood as well as it should. This can happen for a variety of reasons.
heart failure: When the heart loses its ability to push enough blood through the blood vessels, it is called heart failure.

This information does not replace medical advice. If you are concerned you might have a medical problem please ask your Boots pharmacy team in your local Boots store, or see your doctor.