Heart function recovered quickly in children with COVID-19-related MIS-C condition

Jan. 21, 2022

Heart function recovery returned within three months in children who developed COVID-19-related multisystem inflammatory syndrome (MIS-C), according to new research published in the Journal of the American Heart Association, an open access, peer-reviewed journal.

MIS-C is a new illness identified during the COVID-19 pandemic that affects children about four to six weeks after exposure to COVID-19. The condition has some overlapping symptoms with Kawasaki disease, however, MIS-C is associated with more profound inflammation. MIS-C can cause inflammation in different parts of the body, including the heart, lungs, kidneys and gastrointestinal organs. About 80%-85% of MIS-C cases across the U.S. and Europe have involved the heart’s left ventricle.

This study details the cardiovascular complications or damage found during a three-month follow-up period to assess the short-term impact of MIS-C. It also employs newer cardiac measurements, known as “strains,” to assess heart function related to MIS-C. Strain testing is a more sensitive tool that can detect whether an area of the heart is deformed or if there are any subtle changes in heart function during cardiac contraction and relaxation.

“There is limited data at this time about how frequently and how long we should monitor heart function during the recovery state of MIS-C after the child leaves the hospital,” said the study’s senior author Anirban Banerjee, M.D., a professor of clinical pediatrics at the University of Pennsylvania Perelman School of Medicine and an attending cardiologist with the Cardiac Center at the Children’s Hospital of Philadelphia, both in Philadelphia.

“Given that MIS-C was identified as a result of the COVID-19 pandemic, treatment protocols have not yet been standardized and follow-up care varies greatly, which may lead to confusion and anxiety among families of patients and their care team. Our research team hoped to provide some guidance and reduce the ambiguity on optimal care approaches, especially as it relates to sports participation,” Banerjee added.

The study found:

  • Based on echocardiogram imaging, systolic and diastolic function in the left ventricle and systolic function in the right ventricle improved quickly within the first week, followed by continued improvement and complete normalization by three months.
  • 81% of patients lost some contractile function in the left ventricle during the acute phase of illness, yet, by months three and four, contraction function had returned to normal.
  • MIS-C did not cause lasting coronary artery abnormalities. During the initial hospitalization, 7% of patients had evidence of some heart malfunction, however, all scans were normal by the three-month follow-up.
  • Using strain parameters to measure cardiac function, the results suggest that there is no subclinical cardiac dysfunction after three months.

“Recovery among these children was excellent,” Banerjee said. “These results have important implications for our healthcare teams managing care for children with MIS-C. Our findings may also provide guidance for a gradual return to playing sports after cardiac clearance three to four months later. Tests needed for clearance include electrocardiogram and echocardiogram. We also recommend cardiac MRI for children who have highly abnormal baseline cardiac MRI during the acute stage or show evidence of continued severe left ventricle dysfunction.”

The study researchers note there are still important gaps in existing knowledge about MIS-C, since COVID-19 and MIS-C are both new illnesses. The most important question yet to answer is how these children are faring one to two years after their initial hospitalization.

American Heart Association release

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