slice and dice: what covid-19 does to the heart

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'i had never seen anything like it before': researchers looking for ways to protect the heart from long-term damage.

by diana duong

published sep 08, 2020

last updated feb 24, 2025

2 minute read

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2 minute read

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what covid-19 does to the heart: "cell equivalent of being brain dead"

in an in vitro (lab) study, heart muscle cells that were infected with sars-cov-2 became damaged and were unable to properly beat because the fibres that help the muscles contract broke apart into small pieces. getty images

since the start, covid-19 has been labelled as a respiratory infection, given the damage it wreaks on lungs, but new research suggests it could just as well be a heart disease.

more evidence is showing the impact covid-19 has on multiple organ systems, including the heart, gastrointestinal (gi) tract, and kidneys. covid-19 can cause heart dysfunction in up to 50 per cent of patients, even those with mild symptoms. people without any history of cardiovascular disease have also been shown to have heart damage after infection with the virus.

in a new study based on cell culture, researchers from san francisco’s gladstone institute added sars-cov-2 viruses to human heart cells grown in a petri dish and were alarmed to find that it diced the long muscle fibres that keep hearts beating into short fragments.

but it’s not the first time they had seen such frightening damage. the same phenomenon was observed in heart tissue from autopsies of deceased covid-19 patients.

“early on in our experiments, we noticed that many of the cardiomyocytes (a type of cell in the heart) were exhibiting some very strange features,” said todd mcdevitt, senior investigator of the study, in a statement. “what we were seeing was completely abnormal; in my years of looking at cardiomyocytes, i had never seen anything like it before.”

left: a healthy heart muscle with fibres that help the heart muscles contract. right: the virus that causes covid-19 slices these fibres into small pieces and impacting the heart cell’s ability to beat. (image: gladstone institute.) gladstone institute

“the sarcomere disruptions we discovered would make it impossible for the heart muscle cells to beat properly,” said dr. bruce conklin, another senior investigator on the study.

researchers say that nuclear dna information was missing from many of the heart cells, which means the cells would not be able to perform any of its normal functions.

“it’s the cell equivalent of being brain dead,” says conklin. “we believe they are unique to sars-cov-2 and could explain the prolonged heart damage seen in many covid-19 patients.”

this adds to a body of research showing covid-19’s effect on the heart, even long after the virus is gone.

a study from germany published in july looked at 100 patients who recovered from covid-19 and found that 60 of them showed signs of ongoing heart inflammation, while 18 had other cardiac issues. one-third of participants had required hospital treatment, but none were classified as having serious covid-19 symptoms.

researchers said that unlike other organs in the body, the heart is not able to regenerate tissue. if someone became infected with covid-19, even if it a mild infection, it is possible they could develop heart disease years down the road.

“it will be important to identify a protective therapy, one that safeguards the heart from the damage we’re seeing in our models,” says mcdevitt. “even if you can’t prevent the virus from infecting cells, you could put a patient on a drug to prevent these negative consequences from occurring while the disease is present.”