Risk for lasting heart condition after COVID? Experts say athlete studies not clear

As college athletes return to their sports teams amid the COVID-19 pandemic, experts in cardiology are wary of potential long-term impacts of the virus on young, fit people.

Can COVID-19 affect the hearts of those constantly engaging in rigorous physical activity? And to what extent?

In recent studies -- albeit small ones -- some COVID-19 patients had signs of myocarditis, a condition where the heart muscles become inflamed, show up on cardiac MRI scans.

While myocarditis is rare and often resolves itself on its own, it can also be fatal in certain instances.

"We tend to think whatever doesn't kill you makes you stronger but that's absolutely not true -- what doesn't kill you can still leave lasting damage on your body," said Montreal cardiologist Dr. Christopher Labos. "The vast majority of people do recover from COVID, but a small number don't.

"And it's not just about being dead or alive, it's also about consequences with lasting damage."

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In a study by Ohio State University, 26 athletes who had previously tested positive for COVID-19 were given cardiac MRIs. The scans showed scarring and other evidence of myocarditis on 15 per cent of them while another 30 per cent had damage or swelling that couldn't definitively be linked to the syndrome.

Dr. James McKinney, a cardiologist at UBC, says a myocarditis diagnosis in 15 per cent (four out of the 26 patients) is much higher than expected.

But since the study did not run MRIs on the same athletes before their COVID infections, there's no way of knowing if the scars were already there.

"Different types of flu viruses have been associated with it, but whether SARS-CoV-2 has a higher incidence of myocarditis, we just don't know," McKinney said. "A better study would be if you had athletes coming in who had COVID and athletes coming in after the flu, and looking at the MRIs to compare.

"It's possible that COVID-19 causes more myocardial injury than the regular cold virus, but we can't say for sure."

When a virus affects the heart, it initiates an inflammatory response, explained Jack Goodman, a professor of cardiac health and exercise at the University of Toronto.

The mortality rate for viral myocarditis is "about one or two out of a million."

"So it doesn't happen a lot. But it is a concern," Goodman said.

Concern around COVID-19 led NCAA's Big Ten Conference, which includes Ohio State, to cancel its fall sports schedule in August. The conference reversed that decision last week, however, saying it will start its football season next month.

U Sports, the governing body of Canada's university athletics, has nixed all its fall championships but is leaving the cancellation of each sport's season to the schools and conferences themselves. Some are going ahead with football practices despite not having actual games.

Myocarditis has been linked to sudden death in young athletes in small numbers of cases, McKinney said, but potential dangers of the condition becomes harder to decipher if symptoms aren't present.

Of the 26 athletes scanned in the Ohio State study, only two reported shortness of breath. Echocardiograms (heart ultrasounds) and electrocardiograms (ECGs) also came back normal.

"The presence of the scar doesn't necessarily mean a clinical diagnosis of myocarditis," McKinney said. "And we don't know the long-term prognosis of the scar -- will it resolve, will it have extreme outcomes?"

Plenty of high-profile athletes have tested positive for COVID-19, including world No. 1 tennis player Novak Djokovic and Denver Broncos linebacker Von Miller. But few -- that we know of -- have developed myocarditis.

Eduardo Rodriguez, a 27-year-old Boston Red Sox pitcher, is one of them, missing the MLB season with the condition doctors believe stemmed from his previous COVID infection.

Whether you're a professional athlete or an amateur gym-goer, McKinney says anyone recovering from COVID-19 shouldn't be working out until at least one week after symptoms have completely resolved.

At that point you can start back up gradually, he says, but should stop if cardiac symptoms develop.

"If you feel palpitations, your heart beating funny or going too fast, feeling dizzy or faint with exercise, chest pain, shortness of breath -- that's when you should seek medical attention," said McKinney, who along with Goodman is part of a group of cardiologists and experts writing guidelines for returning to sport after a COVID infection.

Goodman says that advice goes for a cold or flu, too. If you're showing symptoms, "you shouldn't be exercising."

While myocarditis is rare, infectious disease expert Dr. Zain Chagla of McMaster University says the prevalence of COVID worldwide means we can expect cases of viral myocarditis to rise.

He stressed that most patients with myocarditis will revert back to normal, but others will maintain "chronic cardiac complication, heart failure, and occasionally significant disease that requires transplant.

"So, anything that triggers myocarditis is a concern."

Labos, who also has a degree in epidemiology, says COVID can have lasting impacts on various parts of the body, including the brain, lungs and heart. And we don't know the full extent of that yet.

He stressed that most young people contracting COVID-19 will likely recover, but the best way to avoid a possible COVID complication is to avoid the virus in the first place.

"So stay home, wear your mask, wash your hands, all the basic stuff."

This report by The Canadian Press was first published Sept. 23, 2020.