Researchers in Germany discovered something odd about the aftereffects of COVID-19, not when the spread of the virus first started stirring global panic, but rather months down the line. The possibility of a heart condition, myocarditis, was found at alarmingly high rates in an MRI imaging study of 100 people who had been recently infected with the coronavirus. 

When the research paper was first published in JAMA Cardiology, a well-known journal read by cardiologists around the world, it instigated a wave of panic. 

“Almost every virus known to man can cause myocarditis,” Dr. Nancy Sweitzer, the director of the University of Arizona Sarver Heart Center and a cardiologist and researcher, said. “[However], 99.99% of people don’t get myocarditis [from viral infections].”

Myocarditis wasn’t formally observed in patients in the first five to six months of the pandemic. It isn’t a common symptom of any known virus — though as Dr. Sweitzer mentioned, it is documented as a rare, well-known complication of many viruses, including the one that causes the common cold — and to see MRI patterns consistent with myocarditis suddenly show up in 60% of participants was, to say the least, a problem for doctors and most certainly a problem for former COVID-19 patients. 

Myocarditis is the condition in which the virus causes the immune system to attack the heart, and inflammation ensues. While it isn’t commonly severe, at times, it can be fatal. The inflammation, if severe and prolonged, can cause scarring, and the scarring causes abnormal electrical signals.

The heart is run by electrical signals that pulse rhythmically to drive each heartbeat. Scarring can disrupt normal electrical signaling and cause arrhythmia, the condition in which patients have an irregular heartbeat, and patients usually experience symptoms like chest discomfort or shortness of breath as scarred heart tissue works harder to pump blood throughout the body.

If arrhythmia develops, it can then present itself in symptoms like light-headedness, loss of unconsciousness caused by a sudden drop in blood pressure or even sudden death. 

The myocarditis observed in patients in the first five to six months of the pandemic appeared to be related to inflammation in the entire body and tied to a multi-organ inflammatory syndrome, rather than myocarditis isolated in the heart.

Myocarditis found solely in the heart muscle isn’t a common symptom of any known virus — though as Dr. Sweitzer mentioned, it is documented as a rare, well-known complication of many viruses, including the one that causes the common cold — and to see MRI patterns consistent with myocarditis suddenly show up in 60% of participants was, to say the least, a problem for doctors, and most certainly a problem for former COVID-19 patients. 

This can be especially alarming for athletes — strenuous or competitive sports and exercise, Sweitzer said, can be potentially dangerous about three to even six months after COVID-19 infection. Sometimes, symptoms don’t show, and if myocarditis remains undetected in an athlete, sudden cardiac arrest can occur.

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In an incident in 1993, a college basketball player suddenly collapsed on the court and passed away. It was found to be caused by undetected myocarditis. Exercise, according to a paper published in the American College of Cardiology, can worsen and exacerbate myocarditis symptoms, and as observed, to fatal extents like the one in 1993, which left organizations like the Pac-12 and the Big Ten deciding to cancel college football in the fall of 2020 when rampant testing was quickly conducted and several athletes were found with the condition, then finding the Big Ten reversing its decision just a month later. 

It’s important to have an AED on hand, and subsequently necessary to have people who know both how to use the AED as well as perform CPR present if sports are continuing, Sweitzer explained.

Another problem developing in patients after recovery from COVID-19 is vascular inflammation, which is inflammation of all the blood vessels in the body, Sweitzer said. Blood clots unlike any she has seen before line entire blood vessels or clot in the arteries in the heart; several patients are coming in who’ve had COVID-19 three, four, even six weeks ago.

They form differently from regular blood clots. The onslaught of new unknowns of COVID-19 is only evidence that it’s better to be cautious, Sweitzer explained.

“It’s not garden-variety myocarditis. We’re so early — it’s a brand new virus, and we’re learning as fast as we can. One of the things I wonder is if these imaging findings might have to do with what we call microthrombi, little blood clots that are forming in tiny little blood vessels in the heart muscle, and leading to this imaging finding that looks like myocarditis, but when you look at the heart under the microscope, [it] may or may not be myocarditis.”

She wryly added, “And we can’t look at the heart under the microscope so easily.”

As for anyone who’s had COVID-19 before, Sweitzer warns that we can be sure antibodies last for three weeks after being infected by the virus, but beyond that, we can’t. In the very short-term, we’re protected.

However, considering the recent reports of reinfection, she advises that both for the sake of protecting at-risk populations and for preventing unknown risks to personal health, it’s better to continue following protective measures and avoid large gatherings until the pandemic abates.

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