Coronavirus causing heart disease in some patients, study finds

The coronavirus can cause heart disease in some patients, even those who had relatively mild symptoms of COVID-19, a new study has found.

The study, published in the journal JAMA Cardiology, examined a group of 100 COVID-19 patients. Some were sick enough to have been hospitalized, and some had a mild enough illness that they were discharged and left to recover at home.

Around 60 per cent of those patients had evidence of myocardial damage – inflammation of the heart muscle, which can be mild, or eventually increase the risk of serious cardiac problems like heart failure.

“This is actually quite scary,” said Dr. Gavin Oudit, a cardiologist at the Mazankowski Alberta Heart Institute and professor at the University of Alberta.

“It’s not the acute, decompensated very sick COVID-19 patients that are in ICU. These are patients that had symptoms but had a resolution of the virus.”

But the study may not be quite as scary as it appears at first glance, according to Dr. Dinesh Thavendiranathan, a cardiologist at the Peter Munk Cardiac Centre in Toronto.

The study compared COVID-19 patients to a control group who had similar pre-existing risk factors for cardiovascular disease, but who didn’t have the virus. In that control group, around 40 per cent of patients showed signs of myocardial damage, meaning that the increased burden from COVID-19 wasn’t quite as high as it looks.

However, he said, cardiovascular disease among COVID-19 patients is definitely a concern.

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There have been other studies earlier in the pandemic, mainly from China, that found that around one in five COVID-19 patients admitted to hospital showed signs of heart injury – and those with heart injury tended to get more severe disease outcomes, he said.

“We have known from the beginning that if you were to develop COVID-19, you are likely to develop cardiovascular disease.”

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Exactly how likely is still unknown, he said, though he is working on a research project to look at this issue. While the research is still ongoing, he hasn’t seen these kinds of high numbers yet, he said.

The other major question, to him, is how permanent this injury might be and what that means for the patient’s health. If there is inflammation to the heart but it’s gone in six months, then it might not be very consequential, he said. He hopes more studies follow patients long-term to see if the injury persists.

The long-term consequences could be serious, Oudit said, including an increased risk of heart failure down the road, though there are treatments for myocarditis that could lessen this risk.

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Many viruses can cause myocarditis, he said. Similar problems were observed in the original SARS pandemic in 2003, he said, and more ordinary parvoviruses are known to cause heart inflammation.

The SARS-CoV-2 virus targets a receptor found throughout the body – including in the heart – he said, so he’s not surprised that it seems to be causing heart damage.

“It’s not a respiratory illness, it’s a systemic illness,” he said.

While the virus might directly cause heart injury in itself, patients who already have cardiovascular conditions could also get worse if they catch the virus, Thavendiranathan said, because of increased stress and inflammation in their bodies.

For both Thavendiranathan and Oudit, this study highlights the need to follow up with COVID-19 patients after their recovery, to check for and treat any lasting issues.

“We’re going to have to be vigilant,” Oudit said. “We’re going to have to monitor COVID-19 patients carefully. And I think once this pandemic subsides, it’s unlikely to go away completely.

“Follow up care for patients with COVID-19 is going to be important, and certainly the cardiovascular care is going to be a big part of that.”