What is myocarditis? How is it linked to COVID-19? And why is it a concern for athletes? UNC Blood Research Center scientist Silvio Antoniak, PhD, explains.


One of the more concerning side effects of COVID-19 infection is myocarditis — a once rare condition of inflammation of the heart, leading to scar tissue build-up and a weakening of the heart. A study published last month in The Journal of the American Medical Association found that 60% of participants who had recovered from mild or moderate COVID-19 infections had evidence of myocarditis.

While most cardiovascular conditions are associated with older populations, myocarditis most often affects otherwise healthy, young, athletic types.

What is myocarditis and how is it linked to COVID-19? Why should athletic individuals be concerned? The Well spoke with myocarditis researcher Silvio Antoniak, PhD, assistant professor of pathology and laboratory medicine in the School of Medicine’s Blood Research Center, to learn more.

What is myocarditis and how is it linked to viral infection?

Myocarditis is inflammation of the myocardium, and the myocardium is the heart muscle. There are three major causes of myocarditis — parasites, certain drugs and infections by bacteria and viruses. For example, a parasite might enter the heart and cause inflammation, such as with Trypanosoma cruzi, which causes Chagas disease. Cocaine abuse can cause inflammation in the heart. That’s drug-induced myocarditis. Or you can have an infection. Influenza has been shown to be detectable in heart biopsies. So have the genomes of other viruses — herpes, parvovirus B-19, coxsackievirus. But just because you have the flu or some other viral infection doesn’t mean you’ll get myocarditis. It’s unknown why certain people develop myocarditis and certain people don’t develop it. It could also be that the body’s immune response to the infection causes the myocarditis.

Why is viral myocarditis a concern for athletes?

At least for pre-COVID-19 myocarditis research, the incidence of viral myocarditis was shown to be higher in younger people, from puberty to 30 years of age. The incidence in males was higher than females. One thing we can say is the female sex hormones protect against myocarditis or reduce the risk.

Athletes might experience a ‘double hit.’ They have an underlying virus infection in the heart, and then they have a stress event — rigorous exercise — which causes a second hit to the heart.

It could also be that it’s more visible in athletes. When a person plays sports, more people recognize myocarditis than when it happens to a kid somewhere on a playground. I think exercise has a role but also the visibility of the event.

So it sounds like anyone in the general population could have viral myocarditis and recover, but the risk for athletes is that they are pushing themselves physically.

That is correct.

Before COVID-19, how much of a concern was viral myocarditis for athletes?

I don’t think it was much of a concern. The NIH said viral myocarditis pre-COVID-19 was a rare disease. One study from Minnesota calculated that one in 200,000 athletes per year died of sudden cardiac arrest. But that was before COVID-19.

Read the rest of this story by Logan Ward at The Well.