Heart Muscle Cells Do Regenerate, New Treatments May Speed Up This Rate.
Lots of research. These quotes are from two different studies.
"By using DNA samples from many hearts, the researchers estimated that a 20-year-old renews about 1% of heart muscle cells per year and about 45 percent of the heart muscle cells of a 50-year-old were generated after he or she was born."
"This latest finding raises the possibility of someday using induced pluripotent stem cell (iPS) technology to take a skin cell from a patient with heart disease and use it to generate muscle tissue to repair the diseased heart."