A man from Derbyshire was saved after passers-by used a nearby defibrillator to bring him round after going into cardiac arrest.
Alan Thompson from Swadlincote was on a bike ride with his brother when he suddenly suffered a cardiac arrest before collapsing.
People nearby used the device to deliver an electric shock to his heart. It brought Alan back to life, before paramedics arrived to take him to hospital.
Now the British Heart Foundation and the NHS, working with the technology giant Microsoft, have announced plans to map all the country's devices.
It will help ambulance services direct people to their nearest defibrillator and, it's thought, could save thousands of lives.
Previous research found just 3% of patients who suffer cardiac arrests outside of hospital are treated with public access defibrillators.
The new project will see a comprehensive map of defibrillators across the UK created over the next 12 months.