New research has shown that GPs have become a vital extra line of defence for patients suffering a cardiac arrest - thanks to a pioneering move over 20 years ago by the British Heart Foundation (BHF) to supply surgeries with defibrillators.
The charity has funded more than 2,000 defibrillators in GP surgeries since 1985, when the entire proceeds of that year's London to Brighton Bike Ride were devoted to the purpose.
Dr Michael Colquhoun, from the University of Cardiff, analysed the data from 555 attempts by GPs to resuscitate cardiac arrest victims using these defibrillators - and found that almost half of all patients (46%) survived when the doctor was present or nearby when they went into cardiac arrest.
A cardiac arrest is when the heart stops, or goes into a chaotic rhythm, and in 60% of cases in the audit, this followed a heart attack - when a blood clot in a coronary artery blocks the blood flow to the heart muscle.
Restoring a normal heartbeat quickly is crucial. Currently in the UK, a person's chance of surviving a cardiac arrest outside of hospital is just 2-3%, and their chances drop by 14%1 for every minute that passes without defibrillation.
Dr Colquhoun's study underlines just how much difference having a defibrillator close by can make to a patient's survival hopes - and how GP surgeries are an ideal place to locate them within communities.
The study shows that about half of all the patients who die from heart attacks do so in the first hour after the onset of symptoms such as chest pain.
Dr Colquhoun says: "This study shows very clearly the life-saving value of equipping GPs with defibrillators.
"It confirms that GPs are often successful at resuscitating patients who arrest in their presence or do so shortly before they arrive - and because they are at the heart of their communities, GPs are often well placed to reach vulnerable patients before or very soon after a cardiac arrest."
The study also found:
75% of the cardiac arrests occurred in the patient's home or in a public place. Only a minority (15%) of the arrests occurred in the surgery where skilled help might be available.
Unsurprisingly, the sooner the shock was given, the better - the most dramatic results were in patients in the early stages of heart attacks who actually arrested in front of the doctor. Shockable rhythms were present in nearly 85% of these cases, and of these, almost 70% survived to be discharged from hospital.
Sometimes the doctor was not actually with the patient when they arrested, but provided they could attend within four minutes, 64% of those with shockable rhythms survived.
When the doctor attended later - because they were summoned after the arrest, or because the patient arrested while the doctor was en route - 11% of patients survived.
Katharine Peel, BHF Head of Emergency Life Support, said: "Because people suffering heart attacks often doubt the severity of their symptoms, we know they often call their GP rather than dial 999.
"Our current 'Doubt Kills' campaign is trying to change that tendency - urging people to call 999 when they experience symptoms such as chest pain so they get the fastest and best possible treatment from paramedics.
"But this study provides some reassurance that those heart attack victims who do call their GP still have a reasonable chance of survival if they go into cardiac arrest - but only if the GP has a defibrillator.
"We would urge all GPs who do not have a defibrillator in their surgeries to take notice of the dramatic results of this study and consider applying to the BHF for funding."
The BHF has produced a booklet for GPs about defibrillators and resuscitation. It can be ordered by calling 0870 600 6566. To discuss an application for funding, GPs should call 020 7487 7167.