I don't mean to make light, this is terrible. But when I see myocarditis this is my first thought. I didn't even know it existed pre-covid, I had never heard of it.
"Though cases of myocarditis and pericarditis are rare, when cases have occurred, they have most frequently been seen in adolescent and young adult males within 7 days after receiving the second dose of an mRNA COVID-19 vaccine; however, cases have also been observed in females, in other age groups, and after other doses."