The authors of a report into defibrillators reviewed all calls made to the South Central Ambulance Service between September 2011 and August 2012 following a heart attack.
During the course of the study, the service received 1,035 calls about confirmed cardiac arrests away from a hospital - the equivalent of one for every 600 members of the public each year.
For 44 of these incidents (4.25%), in 34 different locations, the caller was able to access an external defibrillator. However, it was successfully retrieved and used in less than half the cases (18 cases) before the arrival of an ambulance.
A shortage of defibrillators - which shock the heart - and a lack of public awareness could be costing thousands of lives every year, research suggests.
Experts found that fewer than 2% of heart attack victims in one county in England were treated with the device before an ambulance arrived - a figure described as "disappointingly low".
The British Heart Foundation (BMF) estimates that 60,000 heart attacks occur out of hospital every year across the UK.
Report author and NCEPOD lead clinical co-ordinator Dr George Findlay said:
Cardiac arrests in hospitals could be prevented if doctors recognise and act on early warning signs more quickly, a health watchdog has said.
More than a third (38%) of cardiac arrests in acutely ill patients could be avoided by improving their assessment and response to deterioration, researchers found.
Experts from the National Confidential Enquiry into Patient Outcome and Death (NCEPOD) criticised senior doctors for failing their patients by not supporting junior colleagues.
The study, Time To Intervene?, found that warning signs were not picked up in 35% of those patients, not acted on in 56% and not communicated to senior doctors in 55%.