Results from the US study, published online in The Lancet medical journal, offer hope for patients with heart failure, where the pumping action is diminished.
Researcher Eduardo Marbn, director of the Cedars-Sinai Heart Institute, said: "While the primary goal of our study was to verify safety, we also looked for evidence that the treatment might dissolve scar and re-grow lost heart muscle.
"The effects are substantial, and surprisingly larger in humans than they were in animal tests."
Shlomo Melmed, dean of the Cedars-Sinai medical faculty, said the treatment could mark a new era in heart medicine.
"This study shows there is a regenerative therapy that may actually reverse the damage caused by a heart attack," he said.
As an initial part of the trial in 2009, Marbn and his team completed the world's first procedure in which a patient's own heart tissue was used to grow specialised heart stem cells.
These cells were then injected back into their hearts. All the patients monitored - with an average age of 53 - had survived heart attacks.
There were eight serving as controls, receiving conventional care including prescription medicine, exercise recommendations and dietary advice.
The other 17 allocated to receive the stem cells had a minimally invasive biopsy, under local anaesthesia.
Previous trials have shown remarkable results from using stem cells, but they have been taken from different areas of a patient's body.
Stem cells can become almost any type of cell, but are in short supply in adult organs. Several thousand patients worldwide have received them from bone marrow, but this trial seems to confirm that cardiac stem cells may be the most effective for heart damage.
- DAILY MAIL
