A jab that allows damaged hearts to heal themselves and could be given by paramedics in the back of ambulances is being developed at a British university.

Scientists at Imperial College London hope that giving heart attack victims an injection of stem cells will trick the organ into repairing itself, saving lives and greatly cutting the odds of further ill health.

Crucially, and unlike other techniques being tested on patients in the UK, the cells they plan to use are from a person’s own heart, an innovation they believe increases the odds of the treatment being a success.

They are close to applying for permission to test the jab on patients.

If trials on heart attack survivors are successful, the injection could eventually be given by paramedics just minutes after a heart attack and before patients even reach hospital.

A jab that allows damaged hearts to heal themselves and could be given by paramedics in the back of ambulances is being developed at Imperial College London

The jab is one of several treatments being researched by the British Heart Foundation as part of its multi-million-pound Mending Broken Hearts project to improve the care of heart attack patients.

The aim is to cut the odds of heart failure, in which the heart, weakened by one, or a series of heart attacks, struggles to pump blood around the body.

In the most severe cases, the lungs ‘drown’ in fluid.

Treatments range from drugs to transplants but with 40% of those affected dying within a year of diagnosis, heart failure has a worse survival rate than many cancers.

Doctors and scientists around the world are trying to use stem cells – “blank” cells able to turn into various types of tissue – to shore up ailing hearts.

But most have focused on cells taken from bone marrow and improvements have been slight.

The Imperial team believes that stem cells from the heart will be much more successful.

These cells are extremely rare, with just 300 per million normal heart cells, meaning the lack the power needed to repair the damage wrought by a heart attack.

But the scientists have found a way of extracting them from a patient’s own heart, and growing them in huge numbers the laboratory, before injecting them back into the hear

Once there, they patch up the ailing tissue, with tests on mice showing stem cells taken from the animals’ hearts trigger the growth of new tissue and blood vessels.

The human version of the jab has also been tested on pigs and the researchers are one to two years away from applying for permission to test the treatment on patients.

With it taking three to four months to grow enough cells for each jab, the first patients will be treated several months after a heart attack.

But in time, it may be possible to create a one-size-fits-all jab, allowing almost immediate treatment, said researcher Professor Michael Schneider.

Esther Rantzen, who is backing the Mending Broken Hearts appeal and whose late husband, the documentary maker, Desmond Wilcox battled heart disease for years, said: “If hearts learn to heal themselves, then people who are bed-bound, who are imprisoned in their own homes, who can’t walk upstairs, who can’t involve themselves in any physical activity could be restored to health and their family life greatly improved.”

Prof. Michael Schneider is also trying to find ways of stopping cells from dying during a heart attack.

Other work being funded by the BHF includes research into a pill that could be given in advance to those at high risk of heart attacks and patches of cells that could patch up the heart.

Professor Peter Weissberg, the charity’s medical director, said that despite advances in cardiac medicine, a good treatment for severe heart failure has remained elusive.

“Although we have been able to prevent heart attacks and treat people with heart attacks when they occur, we haven’t been able to stop the damage that occurs when a heart attack takes place.

“The reason we are making such a noise about it now is that science has progressed to a point where it looks biologically feasible that we might be able to create new heart cells to repair the heart.

“Ten years ago, that would have been science function.”