Sars-CoV-2 was found in the hearts of most people who died as a result of complications from the virus, a small study has found. Scientists in the US examined about 1,000 pieces of heart tissue from 41 patients, in what is thought to be the most detailed study of its kind. The virus, which causes Covid-19, was found to be present in the hearts of 30 of them. It was only these patients who developed new abnormal heartbeats, which were fast, irregular or included early or extra heartbeats, compared with the other patients. Scientists do not know why the virus attacked the hearts of the patients. "Comorbidities are present in many patients with Covid-19 with critical illness," said the scientists, who carried out the <a href="https://www.nature.com/articles/s41379-021-00790-1">study</a> at Massachusetts General Hospital. “However, cardiac inflammation was associated with neither the underlying medical conditions nor the composite risk factor scores.” Instead, it correlated strongly with the <a href="https://www.thenationalnews.com/uae/health/long-covid-scientists-and-doctors-grapple-with-unanswered-questions-1.1182976">duration of symptoms</a> and hospital stay, suggesting heart damage may result in "many patients with a long Covid-19 illness prior to death". The authors pointed out the research focused on patients with fatal Covid-19 whose bodies underwent postmortem examinations. They said the results might not be applicable to all patients dying with Covid-19. “In a study of our hospital’s Sars-CoV-2 testing facility, the median age of all patients testing positive for Sars-CoV-2 during the spring of 2020 was 47, with 50 per cent being men, compared with a median age of 67 and 66 per cent men in our autopsy series. “Thus, our observations may not be generalisable to all patients with Sars-CoV-2 infection.” Some doctors have questioned whether Covid-19 is a vascular disease, rather than a respiratory one, due to its ability to cause clots. In a <a href="https://www.nejm.org/doi/full/10.1056/NEJMoa2015432">study</a> published last summer, researchers compared the lung tissues of people who died from complications related to Covid-19 with those who died from influenza. Surprisingly, they found that lung tissue of Covid-19 patients had nine times as many tiny blood clots as those of the flu patients. In addition, the endothelial tissue in coronavirus-infected lungs exhibited “severe” injury. “The surprise was that this respiratory virus makes a beeline for the cells lining blood vessels, filling them up like a gumball machine and shredding the cell from the inside out,” Dr William Li, a vascular biologist who led the study, told broadcaster NPR. “We found blood vessels are blocked and blood clots are forming because of that lining damage.”