Pioneering stem cell treatment could be used to repair the damaged tissue of heart attack victims, according to a doctor.
Two heart attack victims have already undergone the process, which involves taking a small amount of the patient's bone marrow and injecting it into their arteries within hours of the attack.
The stem cells, taken from the lower back under local anaesthetic, are purified before being "infused" into the damaged area.
It is thought the stem cells can rejuvenate or replace damaged cells, restoring a healthy heart.
Dr Anthony Mathur, senior lecturer and consultant cardiologist at Barts and the London NHS Trust, said: "It's about using the patient's own cells to see if they can repair the damage that the heart attack has caused.
"The dream is to turn the clock back, to restore heart function to what it was before the heart attack.
"It would be a fantastic achievement."
Dr Mathur, who designed the experiment with Professor John Martin, British Heart Foundation chair in cardiovascular sciences at University College London, said the procedure could completely restore quality of life.
If successful, it will enable patients to return to work quickly, and without the need to take tablets for the rest of their lives.