A 'patch' from heart muscle that can be used to fix scarring left over from a heart attack has been developed by researchers in Israel.
The researchers showed that the technique strengthened the hearts of rats that had suffered heart attacks, reports the BBC.
The 'patch' was grown in abdominal tissue first, then transplanted to damaged areas of the heart.
This is the first experiment to show that such patches can actually improve the health of a heart after it has been damaged.
The researchers measured an increase in the size of the muscle in damaged areas, and improved conduction of the electrical impulses needed for the heart to pump normally.
Heart attacks usually cause irreversible damage to heart muscle. If people survive, then the damaged muscle can cause another serious condition called heart failure.
The researchers, led by Tal Dvir from Ben-Gurion University of the Negev in Beer-Sheva, hope that the procedure may eventually lead to treatments in humans because of its "simplicity and safety".
However, they added "because most patients with heart attacks are old, and multiple surgery can pose a large risk to them, our strategy is not currently an option".
The study has been described in the journal Proceedings of the National Academy of Sciences (PNAS).