A protein treatment could turn back the clock for heart attack patients, reducing their risk of further complications and repairing damaged tissue.

That's the hope of an international team of researchers, who have for the first time developed a way to reverse the loss of elasticity in damaged heart tissue.

Heart attacks leave damaged heart muscle in their wake, which become scar tissue over time.

The tissue isn't the same as healthy heart muscle because it has lost its elasticity and flexibility.

As a result, patients could experience further complications down the line when it comes to pumping and transporting blood, according to findings published in Circulation Research.

Researchers gave rats one injection of tropoelastin - a protein building block that gives human tissue its elasticity - into the heart wall in the days after a heart attack.

They found damaged and scarred heart muscle regained its elasticity and muscle function similar to before the heart attack 28 days later.

The treatment effectively turned back the clock on muscle damage, the University of Sydney said.

"This research showcases the potential of tropoelastin in heart repair and (suggests) further work will show exciting possibilities of its role in future treatments and therapies," lead researcher Robert Hume said.

Dr Hume conducted the research at the Westmead Institute for Medical Research.

He is based at the University of Sydney's Charles Perkins Centre.

The researchers used ultrasound to guide the needle into the heart wall - a less invasive surgical method than those used previously.

Tropoelastin reduced the size of scars and decreased their stiffness, and further tests on human cells in a petri dish showed those given the protein treatment were able to produce elastin.

Tropoelastin could repair the heart because it replicated the body's natural elastic protein, the Charles Perkins Centre's Anthony Weiss said.

Senior study author James Chong said the findings were highly encouraging.

Researchers hoped to continue developing the method so it could eventually be used to treat and improve the lives of the millions of heart failure patients worldwide, he said.