Myocarditis – pronounced my-o-card-eye-tis – happens when the heart muscle (the myocardium) becomes inflamed and swollen.
Overall, this inflammation of the heart muscle and surrounding tissue is rare. It’s most often caused by a viral infection that makes its way to the heart. Influenza (flu), coxsackie, parovirus (the cause of “fifth disease”), and viruses that cause the common cold are a few examples.
You may have heard more about myocarditis recently given concerns over whether the SARS-CoV-2 virus (the virus that causes COVID-19) or the vaccines used to prevent COVID might trigger inflammation of the heart muscle in some people, especially young boys. While cases have been reported, they are still rare.
Myocarditis is more likely to occur from a COVID-19 infection than as a result of vaccination. There are several theories about how COVID-19 might cause myocarditis either directly infecting the heart muscle or through other ways. Research is ongoing.
Other possible causes of myocarditis, include:
Myocarditis can damage the heart muscle. It can also leave scar tissue in the heart, which can disrupt normal heart rhythms and cause symptoms of heart failure for some people.
Use this online resource to learn about myocarditis, how it’s treated, and questions to ask your health care team.