How to use a defibrillator and save a life
If someone is having a cardiac arrest, a defibrillator can save their life by giving a high energy electric shot to the heart.
Sales of defibrillators rose sharply after footballer Christian Eriksen had a cardiac arrest during Denmark's opening game at Euro 2020.
The NHS has worked with the British Heart Foundation and Microsoft to create a national defibrillator network which shows where you can find these devices across the UK.
All of them are free to use.
But what does a defibrillator do and how does it work?
Defibrillator trainer Helen Tennant explains.
Video by Health, Science and Environment Video Journalist: Laura Foster