Shopping centres, football grounds, and railway stations in the region are being supplied with life-saving defibrillators.
Defibrillators restore the heart's rhythm to normal
The British Heart Foundation (BHF) is issuing 240 defibrillators to the East Anglian Ambulance Service.
The ambulance service in Beds and Herts is to receive 105, while Essex is to get 28.
It is part of a campaign to reduce deaths by heart attacks, and volunteers will be trained to operate the devices.
The project is being funded by money from the Big Lottery Fund.
The mobile defibrillators deliver a controlled electric shock to restore the heart to its normal rhythm.
Seven out of 10 heart attacks happen outside of hospital, and currently in the UK only 2% to 3% of people survive.
For every minute that passes, a patient's survival rate drops by 10%, which means having a defibrillator close at hand could make all the difference.
Katherine Peel from the BHF said: "When we meet people whose lives have been saved by defibrillators, we leatn that their value is priceless.
Now, with the crucial help of volunteers and the expertise of the ambulance trusts, we will be able to give many more people a second chance at life."