A major study involving 1.7 million children has found that heart damage only appeared in children who had received Covid mRNA vaccines.
Not a single unvaccinated child in the group suffered from heart-related problems.
https://www.medrxiv.org/content/10.1101/2024.05.20.24306810v1.full.pdf
https://www.no-lockdown.com/wp-content/uploads/2024/10/OpenSAFELY.pdf