A new study into how COVID-19 affects organs in the body has revealed the "completely abnormal" way the virus damages heart cells.
The findings by scientists at Gladstone Institute was published in bioRXiv on August 25, but is yet to be peer-reviewed.
Researchers created three types of heart cells in lab dishes and then exposed them to SARS-CoV-2, the virus that causes COVID-19.
Of the three types of cells, SARS-CoV-2 could only infect cardiomyocytes (heart muscle cells), which contain muscle fibres which are made up of units called sarcomeres which help to produce a normal heartbeat in humans.
But the researchers found SARS-CoV-2 sliced the sarcomeres into small, precisely sized fragments.
"Early on in our experiments, we noticed that many of the cardiomyocytes were exhibiting some very strange features," said study co-author Todd McDevitt.
"What we were seeing was completely abnormal; in my years of looking at cardiomyocytes, I had never seen anything like it before."
His co-author Dr Bruce Conklin said the cut up fragments would make it "impossible" for the heart muscle cells to beat properly.
The researchers found evidence a similar process could be occurring in the hearts of COVID-19 patients as well.
While analysing heart tissue from three COVID-19 patients, they saw the sarcomere filaments were disordered and rearranged - a pattern that was similar to, but not exactly the same as, what was seen in the lab dish experiments.
They also found another abnormality in both the lab dish experiments and the heart tissue from COVID-19 patients where DNA inside some heart cells appeared to be missing.
"It's the cell equivalent of being brain dead," said Dr Conklin.
"Even after scouring scientific literature and conferring with colleagues, we cannot find these abnormal cell features in any other cardiac disease model. We believe they are unique to SARS-CoV-2 and could explain the prolonged heart damage seen in many COVID-19 patients."
The scientists said they hope their study motivates doctors to consider the possible effects of COVID-19 on the heart and they can begin to find a drug which mitigates the effects.
