By Michael Stump, MD
Blanchard Valley Orthopedics and Sports Medicine
While the effects of COVID-19 infection on the lungs are well-publicized, it is not just a respiratory infection.

Coronavirus can also cause a condition called myocarditis, a viral infection of the heart muscle. Just like it affects the lungs, the virus can invade heart muscle cells, causing inflammation and damage. This condition can result in the weakening of the heart muscle and arrhythmias or irregular heartbeats.

A number of viruses can cause myocarditis, but coronavirus seems to have a higher risk than with other common viruses. The risk of myocarditis increases with the severity of the disease; one study has shown that up to 60% of recovered hospitalized patients have evidence of myocarditis.

However, it has also been seen in patients with mild symptoms. A recent small study at the Ohio State University showed that 15% of collegiate athletes infected with COVID-19 had evidence of myocarditis.

Experts believe that exercising while infected with the virus increases the risk of developing myocarditis.

Myocarditis symptoms include chest pain or tightness, shortness of breath, palpitations (sensation of irregular heartbeat), decreased exercise tolerance and swelling in the extremities.

At its most severe, myocarditis can cause sudden cardiac arrest and has been linked with 10%-20% of all sudden deaths in young athletes. COVID-19 myocarditis has been linked to several sudden cardiac deaths in patients who only had mild viral infection symptoms.

Because of the risks of myocarditis developing in patients with COVID-19 infection, the American Medical Society for Sports Medicine and the American College of Cardiology has published recommendations concerning COVID-19 infection and exercise.

They recommend that anyone diagnosed with COVID-19 infection should be asymptomatic for at least 10 days before considering returning to exercise. If the patient wishes to return to strenuous or vigorous exercise, they should see their primary care provider for cardiac screening before participating.

The screening may include a review of symptoms, physical examination, EKG, blood tests for damage of heart muscle cells, and/or an echocardiogram or ultrasound of the heart. For patients with positive findings on the above evaluation, consultation with a cardiologist and cardiac magnetic resonance imaging is often recommended.

If there are no signs of myocarditis, experts recommend a gradual increase in exercise intensity over at least one week, monitoring for symptoms such as chest tightness, exercise intolerance or shortness of breath. If any of these symptoms occur, the athlete should stop the exercise immediately and contact their primary care provider for further evaluation.

Since COVID-19 myocarditis is a newly discovered condition, we do not know the natural history of people diagnosed with this disorder. In particular, we do not know whether the damage will be temporary or permanent, but experts hope that most athletes diagnosed with COVID-19 myocarditis will be able to return to their previous level of competition.

Recommendations for treating other types of myocarditis typically involve rest from exercise for three to six months and repeat testing to ensure a return to normal cardiac function.

These recommendations for cardiac evaluation after COVID-19 infection are not just for high school and college athletes; anyone of any age who wants to return to strenuous exercises, such as weight lifting or distance running, should be cleared by their primary care provider before restarting their exercise regimen.