Publish date: 10 May 2021

Mild Covid-19 infection is very unlikely to cause lasting damage to the structure or function of the heart, according to a study supported by the NIHR UCLH Biomedical Research Centre and UCLH Charity.

The results of the research, led and sponsored by UCL, should reassure the public, according to the researchers, as the results relate to the vast majority of people who had Covid-19 infections with mild or no symptoms.

The study of 149 healthcare workers recruited from Barts Health and Royal Free London NHS Trusts is the largest and most detailed study to date into mild Covid-19 infection and its longer-term impact on the heart. The British Heart Foundation funded the study, which also received funding from Barts Charity.

The study results come out following concerns that because severe hospitalised Covid-19 infections are associated with blood clots, inflammation of the heart and heart damage, mild infections may cause similar complications. However, up until now, there has been little information specifically looking at this group of people and the effects on the heart further down the line after infection.

Researchers identified participants with mild Covid-19 from the COVIDsortium, a study in London hospitals where healthcare workers had undergone weekly samples of blood, saliva and nasal swabs for 16 weeks. Six months after mild infection, they looked at the heart structure and function by analysing heart MRI scans of 74 healthcare workers with prior mild Covid-19 and compared them to the scans of 75 healthy age, sex and ethnicity matched controls who had not previously been infected.

They found no difference in the size or amount of muscle of the left ventricle – the main chamber of the heart responsible for pumping blood around the body – or its ability to pump blood out of the heart. The amount of inflammation and scarring in the heart, and the elasticity of the aorta – which is important for blood to easily flow out of the heart – remained the same between the two groups.

When the researchers analysed blood samples, they found no differences in the two markers of heart muscle damage – troponin and NT-proBNP - six months after mild Covid-19 infection.

Now, the team of researchers and cardiologists suggest that there is little benefit from screening the hearts of people who’ve had mild infection, and research should focus on those who’ve suffered severe Covid-19, high risk groups or those with ongoing symptoms.

Dr Thomas Treibel, of UCL Institute of Cardiovascular Science UCL who is supported by the UCLH BRC, said: “Disentangling the impact Covid-19 has on the heart has been a challenge. But we’re now at the stage of the pandemic where we can really start to get a grip on the longer-term implications Covid-19 has on the health of our heart and blood vessels.

“We’ve been able to capitalise on our incredible frontline staff who’ve been exposed to the virus this past year and we’re pleased to show that the majority of people who’ve had Covid-19 seem not to be at increased risk of developing future heart complications. We now need to focus our attention on the long-term impact the virus has in those who’ve been hit hardest by the disease.”

Image: abhijith3747 / Adobe Stock