Autopsied hearts show myocarditis link to Covid-19 rarer than previously believed

Nov. 25, 2020

Following a recent review of clinical findings from 277 hearts autopsied from people in nine countries who died from COVID-19, researchers at Johns Hopkins Medicine and the Louisiana State University suggest that myocarditis, an inflammation of the heart muscle, related to the COVID-19 may be a rare occurrence, according to a press release from Johns Hopkins Medicine.

That finding contradicts the results of a German research study, which suggested that 60 out of 100 patients who had recovered from the coronavirus showed signs of the dangerous heart condition via MRI. Shortly after that announcement, stories arose about several athletes with possible COVID-19-related myocarditis — including major league pitcher Eduardo Rodriguez, who was sidelined for the entire 2020 season — that appeared to support the connection. 

The study from Johns Hopkins Medicine and Louisiana State was published online Oct. 29, 2020, in the journal Cardiovascular Pathology.

In this study, the data from the autopsied hearts were published in 22 papers. After careful review, the researchers determined that the rate of myocarditis found in these patients is between 1.4 percent and 7.2 percent. Earlier studies, using imaging of hearts rather than a physical examination of the organs following death, reported rates ranging between 14 percent and 60 percent.

The researchers said that even a low myocarditis rate of 1.4 percent would predict hundreds of thousands of worldwide cases of myocarditis following severe COVID-19. Low rates of myocarditis, they add, do not indicate that individuals infected with SARS-CoV-2 are not having cardiovascular problems, but rather those complications are likely due to other factors such as immune responses or electrolyte imbalances. 

Based on the results of their study, the researchers have created a checklist for pathologists to use when evaluating COVID-19 at autopsy to provide consistency in investigating and reporting cardiovascular pathologic findings.

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