As doctors learn more about the consequences of COVID-19, they are confirming that heart inflammation is rare among hospitalized COVID patients. That's the good news - but those who develop it are much more likely to require intensive care, a new study suggests.
Inflammation of the heart muscle (acute myocarditis) is typically triggered by a virus. It can make it difficult for the heart to pump blood, explained the authors of the paper published recently in the journal Circulation.
"While COVID-19 is a virus that predominantly leads to acute respiratory illness, there has been a small group of individuals who also experience cardiac complications," said co-author Dr. Enrico Ammirati, a cardiologist at Niguarda Hospital in Milan, Italy.
"A small study previously indicated acute myocarditis is a rare occurrence in people infected with COVID-19. Our analysis of international data offers better insight to the occurrence of acute myocarditis during COVID-19 hospitalization, particularly before the COVID-19 vaccines were widely available," Ammirati added in a journal news release.
For the new study, the researchers analyzed data on nearly 57,000 COVID-19 patients admitted to 23 hospitals in the United States and Europe from February 2020 until April 2021.
Acute myocarditis occurred in only 2.4 per 1,000 patients, and was more common in those with pneumonia (57%). Patients with acute myocarditis and pneumonia had a death rate of about 15%, compared to no deaths among those who did not have pneumonia, the findings showed.
One in five patients with myocarditis, most of whom also had pneumonia, needed mechanical support for circulation or died while in the hospital, the researchers reported.
The actual rate of myocarditis may be between 1.2 and 5.7 per 1,000 people hospitalized for COVID-19, according to the study authors.
They explained that some patients believed to have myocarditis based on preliminary testing were not included in the final analysis because they did not meet all of the study's protocols.
"This analysis indicates that, although rare, hospitalized patients with acute myocarditis associated with COVID-19 infection have a much greater need for intensive care unit admission, in up to 70.5% of the cases, despite the average age of the individuals in the study being much younger than expected at 38 years old," said study co-author Dr. Marco Metra. He's a cardiology professor at the University of Brescia Institute of Cardiology in Italy.
For more on COVID-19 and the heart, see the U.S. National Heart, Lung, and Blood Institute.
SOURCE: Circulation, news release, April 11, 2022