Figure 2.

The adult human heart has a low turnover of cardiomyocytes. (A) Radiocarbon dating of the human heart relies upon a pulse (B) of ¹⁴C via the aboveground atomic tests, which was then incorporated into vegetation (via photosynthesis) and consumed by animals and humans. The levels of ¹⁴C found in cardiomyocyte nuclei were used to determine the birth date of the cardiomyocytes. These studies support the notion that 0.5% to 1.0% of human cardiomyocytes turn over each year. While this number is relatively low, these studies emphasize that pathways and subpopulations of cells are present and could be enhanced as a therapeutic initiative. Figure is adapted from references 36–38.