Human hearts can regrow muscle after attack, study shows

For generations, medicine accepted that the heart, once wounded by attack, could not mend its deepest tissue — that the scar was the final word. Researchers at the University of Sydney and the Baird Institute have now challenged that long-held certainty, demonstrating for the first time in living human heart tissue that new muscle cells do emerge after a heart attack. The regeneration is modest, even fragile, but its existence reframes what recovery might one day mean for the hundreds of thousands living in the shadow of heart failure.