Health professionals continue to see heart disease in some young people who have had COVID-19, those who have been vaccinated against the virus, and among student athletes, in general.

Cardiomyopathy is an inflammation and weakening in the walls of the heart.

The Centers for Disease Control and Prevention (CDC) in Atlanta has reviewed vaccine safety data weekly since the start of the U.S. vaccination program and cautions that cases among those who have received the COVID-19 vaccine are “mild and few.” The agency says the condition appears in males more than females, more often following the second shot in a two-dose regimen, and usually around four days after the vaccination.

Coronavirus-related cardiomyopathy was first observed last year in younger people when college athletes resumed play as the pandemic spread in the United States. College sport events generate significant revenues for colleges and universities, and some big schools that draw thousands into stadiums returned players to campus with the hope of public events resuming sooner than later.

In a study of college athletes conducted since last September, a higher incidence of cardiomyopathy, also called myocarditis, has been seen in athletes who contracted the coronavirus, or SARS-CoV-2. Symptoms include shortness of breath, weakness, tiredness, dizziness and abnormal heart rhythm, according to the Mayo Clinic in Minnesota.

“Myocarditis is a leading cause of sudden death in competitive athletes,” researchers wrote in JAMA Cardiology in May, adding, “Myocardial inflammation is known to occur with SARS-CoV-2,” the medical name for the coronavirus.

Another study published in the Journal of the American College of Cardiology in March found that more than one in three “previously healthy college athletes recovering from COVID-19 infection showed … resolving pericardial inflammation.”

Resolving is the key word here: Researchers concluded that “no athlete showed ... features to suggest an ongoing myocarditis,” or inflammation of the heart walls. Knowing when athletes should play or rest is important, and research has not nailed down the long-term effects yet, the researchers said.

“Further studies are needed to understand the clinical implications and long-term evolution of these abnormalities in uncomplicated COVID-19,” they wrote.

Pediatric cardiologist Geoffrey Rosenthal has observed myocarditis in young people, specifically during the pandemic. He has been the team cardiologist for the University of Maryland, College Park since 2020.

“Myocarditis is one of the more common causes of sudden death in athletes,” said Rosenthal.

“If someone had myocarditis, it’s one of the standard recommendations that they not exercise strenuously for three to six months after their diagnosis to allow time for their heart to heal, and lessen their risk of a sudden event,” he said.

The residual health of athletes who have had COVID is being assessed to try to understand the risks.

Ohio State University (OSU) was one of the big universities that brought players back to campus amid the pandemic and detected heart changes in athletes who tested positive for the infection.

It has led the effort to monitor athletes by overseeing a registry of nearly 1,600 COVID-19 positive athletes in the Big Ten sports conference, or a division of 14 colleges and universities among other divisions nationally.

Looking at a smaller sample of 37 athletes diagnosed with myocarditis, 28 didn’t exhibit symptoms, reported OSU.

Rosenthal noted that research and cooperation among universities has advanced detection of myocarditis among young people and student athletes, who are largely asymptomatic, by using magnetic resonance imaging (MRI). The University of Maryland adopted cardiac MRI screening for athletes before almost all other universities in the country as the pandemic was starting, he said.

“The EKG is normal, and their blood tests are normal, and their echo [cardiogram] is OK,” Rosenthal explained. “And then we get the MRI and find out that there's an abnormality that we weren't expecting, and that we never would have found out about had we not done the MRI.

“There's still a lot of cardiac work that's going on in the younger student population,” Rosenthal said.

And this advancement in detection will help other athletes, younger and older.

“There's also hope that it will inform our understanding of COVID in older athletes, in older and non-elite athletes. … the weekend warriors,” he said.

But this research will also help non-athletes whose jobs demand physical labor.

“Other populations that these results might help inform is the military and other professions and occupations in which physical activity is part of what people are doing,” Rosenthal said. “First responders, firefighters, policemen, you know, other people whose jobs have physical demands. In addition to gaining insight into the health of our student athletes what other populations can we help through this work?”