The long-term hope is to treat patients with some sort of stem cell that could turn into beating heart muscle and replace dead cardiac tissue with fully functioning new cells.

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Normally, orderly waves of electric activity pass through the cardiac tissue, causing the heart muscle to contract.

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They found that the stem cells produced growth factors that traveled to the heart, in addition to stimulating the muscle itself to make growth factors that also improved cardiac function.

CNN: Stem cells may offer promise for damaged hearts