The effects of COVID-19 on the heart, both in the long and short term, have been a topic of interest for scientists and health experts since the outbreak of the coronavirus.

Early research found a large portion of deaths caused by the SARS-CoV-2 virus that causes COVID-19 were related to cardiovascular problems and heart damage was prevalent in a percentage of people hospitalized for the virus.

From triggering blood clots in severe cases, to causing inflammation and scarring, it became clear that COVID-19 could do damage to the heart in some serious cases.

But more recently, what has worried scientists and researchers in recent months, is evidence of heart damage reported in mild or asymptomatic cases.

Long COVID-19 and the heart

It was previously understood by health experts that the effects of COVID-19 were not limited to just the acute infection – when the patient begins to show some symptoms – but also what comes afterwards.

Studies found that many patients who had recovered, having had few symptoms to begin with, suffered long-term consequences such as joint pains, shortness of breath, neurological symptoms and other conditions.

While researching the effects of the virus on the heart during the acute infection, scientists at University Hospital Frankfurt in Germany said they stumbled on the heart being part of these long-term consequences in mild and asymptomatic cases by coincidence.

"We decided that we're going to scan patients, we're going to investigate them after they have recovered from the acute illness. This, to a certain extent, brought us to patients who were not so severely symptomatic during the acute phase," Valentina Puntmann, from the Institute for Cardiovascular Imaging at Goethe University Frankfurt (Goethe CVI), told CGTN Europe.

"So many of them perhaps had a little bit of a temperature, but that was it, so in terms of typical COVID-19 symptoms, they didn't always have them. And we were quite surprised by what we have found on the heart because we did not expect this, to be very honest," she explained.

Puntmann, a cardiologist and expert in heart imaging, carried out a study with a team of researchers from Germany and Italy, which involved scanning 100 patients who had recently recovered from COVID-19, including 18 who were asymptomatic.

"We were shocked to see that 78 percent of them have had something on the heart that we could relate to COVID-19 infection. This was mainly inflammation of the heart muscle, that is myocarditis, but also pericarditis, which is inflammation of the heart's lining," Puntmann said.

The team also discovered that they had been symptomatic at that stage, which was weeks or months after the infection, raising concerns of "long COVID-19," which is when patients struggle to recover.

"The presentation is mainly through shortness of breath in young patients who are fit and sporty, they observe they cannot regain the fitness level that they used to have before," Puntmann explained.

However, while this presentation may be prevalent in some cases, along with other identifiers such as palpitations, chest pain, fever, or other symptoms, other cases have none of these markers, making it difficult to be aware of in patients and diagnose.

Young, fit and sporty at risk

The researchers found that a large number of their patients who had shown signs of heart damage weeks after they were infected with COVID-19, were young and sporty.

Puntmann believes it is because younger and fitter patients who contract COVID-19 push through their acute infections and may continue working their body hard, instead of allowing it some time to rest, thus exhausting their heart.

"I must be very clear, we have not actually investigated professional sportsmen, this type of population is usually at risk when it comes to inflammation of the heart, because obviously they put a big strain on their heart as they try to regain their fitness," Puntmann explained.

"So I think it is important to understand what's going on in the heart, and by this, even if we don't yet have any idea how to treat this, inform the patients, inform them about the state of things in their heart and ... also their recovery," she added.

In another study in the U.S., cardiologists screened 54 student-athletes who had returned to their university campus with uncomplicated COVID-19 infections. Almost all of the students tested either had a mild or asymptomatic SARS-CoV-2 infection.

The study, published in the Journal of the American College of Cardiology: Cardiovascular Imaging, found evidence of heart abnormalities in more than one-third of the students tested. While ongoing myocarditis, or damage to the heart muscle, was not found, evidence of pericarditis, or inflammation and excess fluid in the sac around the heart, was frequently found.

Scientists behind both studies have thus raised concerns about athletes or sportspeople contracting the virus, which may then get into the heart and trigger complications such as disrupting the heart's ability to pump blood, leading to sudden heart failures in athletes who otherwise seemed healthy.
 

What can be done about it?

Puntmann said that as heart damage can present itself much further down the line following a COVID-19 infection, even if the patient does not initially show all the symptoms in the acute stage of the virus, it is very important that precautions are taken.

For athletes, scientists agree that what is needed is to minimize the pressure on the body as soon as they test positive for the virus. This means changing their lifestyle to take everything a little bit slower, in order to minimize the risk of heart strain.

But this is also the case for those who may be older and more susceptible to heart conditions. Therefore, Puntmann says that what is also needed is more extensive research into inflammatory conditions of the heart and COVID-19, so that medication and treatments may be developed.

"And this is also, apart from looking at outcomes at the natural course of the disease, the next thing on our 'to-do' list is to start clinical trials with intervention to protect the heart, as in cardio-protection treatment in patients with COVID-19 myocarditis," Puntmann explained.

"We're very academic, cardiac imagers, that's the problem. I'm bringing out the message that we have to become practical, we have to serve patients and patients' needs, that is important ... and I think this is something that we as a community have to sort out very soon," she added.

Cardiologists and researchers agree that there is still much to be discovered about how COVID-19 affects the heart, both in the short and long term, and that they're still scraping the surface of learning about the impact of the virus on our bodies. 

Video editing and animations: James Sandifer