It's one of the biggest killers in the UK. Every year, seventy-six thousand people die following a heart attack.
But many of these deaths could be avoided if the public was more aware of the life-saving equipment that's in our village halls, gyms and work-places.
That's the view of South Central Ambulance Service who're raising awareness of difibrillators in a new campaign.
They want more of us to know how to use them and feel confident in doing so. Juliette Fletcher reports from Wantage on the life-saving technology that we can all use.
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The latest weather for the east with Philippa
The latest weather for the west with Philippa
Met Office issues storm warnings overnight as 80mph winds are expected across the south and east. Storm Imogen is due at around 3am