Doctors are launching a trial to see if patients can be treated using injections of their own stem cells within five hours of a heart attack.
Different therapies will be tested
Early evidence has suggested bone marrow stem cells can be used to repair the damage to the heart muscle that is inflicted during a heart attack.
And that could help prevent subsequent heart failure, which is more of a threat than the initial attack itself.
The trial, run by Barts Hospital in London, will involve up to 100 people.
The project is the first to be funded by the UK Stem Cell Foundation.
Heart attacks kill 108,000 people in the UK each year, and there are currently estimated to be 660,000 heart attack survivors.
It is estimated that heart attacks cost the UK economy around £7bn a year.
Over the last decade, the use of angioplasty, a technique to clear the blocked arteries of patients who have had a heart attack, has helped to reduce the risk of death in the immediate aftermath of an attack.
However, the risk of death from long-term complications, such as the onset of heart failure, remains high.
The new trial, which plans to recruit 100 patients, will combine angioplasty with a stem cell injection to try to combat both problems.
Stem cells are immature cells that have the potential to become any kind of tissue in the body.
Professor John Martin, who has helped design the new trial, said: "Taking heart attack patients to centres where their blocked coronary artery can be opened immediately has led to significant increases in survival and decreases in the damage to heart muscle.
"Previous studies in the heart have shown that stem cell delivery to the heart is safe.
"We will show whether it works in acute heart attack. Our study combines the two new ways of treating heart attack victims for the first time."
Suitable heart attack patients brought to the London Chest Hospital and the Heart Hospital, also in London, will be recruited for the study.
They will undergo angioplasty, in which a catheter is inserted through the groin, and fed up to the blocked artery. A balloon is then inserted to reopen the vessel.
At the same time, a stem cell sample will be taken from the patient's own bone marrow, and treated to separate out the right type of cells.
Once the cells have been prepared, patients will receive the sample into the previously blocked artery through the angioplasty catheter.
Dr Anthony Mathur, who is also working on the trial, said: "If we can demonstrate improvement in the quality of life of patients then this will be a significant step forward in the treatment of heart disease.
"Because the stem cells are taken from the patient themselves there are minimal ethical issues surrounding this procedure. There is also less likelihood of rejection complications."
Professor Peter Weissberg, medical director of the British Heart Foundation, said stem cell therapy had the potential to offer new hope to patients with cardiovascular disease.
But he added: "This trial is unlikely, on its own, to determine the future treatment of heart attacks - and patients shouldn't get the impression there is a panacea around the corner.
"The trial is likely to give us more information - but there is a long way to go."
1 Catheter inserted into blood vessel
2 Device inflated to widen blocked coronary artery
3 Sample of bone marrow taken and stem cells isolated
4 Cells are injected into the heart through the catheter
5 The stem cells develop into new heart muscle cells