Heart Function in Children with MIS-C Returns to Normal within Three Months

Children with multisystem inflammatory syndrome (MIS-C), a post-infectious complication of SARS-Co-V2, regained normal cardiac function within approximately three months of initial treatment, according to a new study by researchers at Children’s Hospital of Philadelphia (CHOP). Cardiac improvement began quickly in the first week of treatment and gradually improved and normalized within three to four months. The findings were published today in the Journal of the American Heart Association, an open access journal of the American Heart Association.

MIS-C was identified during the pandemic as a post-viral hyperinflammatory syndrome affecting children about four to six weeks after exposure to SARS-Co-V2. The condition involves systemic inflammation, affecting organs including the heart, lungs, and gastrointestinal tract. Cardiovascular involvement is common, occurring in 80-85% of MIS-C cases and involving irregularities in the heart’s left ventricle, coronary artery abnormalities, or damage to the heart muscle.

Prior work by this research team demonstrated that utilizing a cardiac parameter known as myocardial strain could measure subtle changes in cardiac function due to MIS-C that were not detected by conventional echocardiography. That study showed that although systolic dysfunction in MIS-C patients recovered quickly within several days, diastolic dysfunction persisted. However, since MIS-C is a newly described disease, long-term studies to determine when normal heart function would return have been scarce. This has led to a lack of follow-up guidelines and confusion in the minds of primary physicians and parents alike.

To provide follow-up data, the researchers analyzed data on 60 children hospitalized with MIS-C due to COVID-19 exposure at one of two Philadelphia hospitals between April 2020 and January 2021. They compared these patients to 60 healthy children of the same ages who had structurally normal hearts. Using conventional echocardiograms and strain parameters, the researchers analyzed the data at four time points: (1) initial hospitalization, (2) within one week of the first echocardiogram, (3) one-month follow-up, and (4) three- to four-month follow-up.

The researchers found that systolic function in the left ventricle and right ventricle recovered quickly within the first week, followed by continued improvement and complete normalization by three months. Approximately 81% of MIS-C patients lost some contraction function in the left ventricle during the acute phase of illness, but contraction function had returned to normal by the three- to four-month follow-up. A very low number (7%) of patients with MIS-C presented with coronary aneurysms, which resolved relatively quickly.

“Our detailed characterization of short-term cardiac outcomes from MIS-C provides evidence that functional recovery and coronary outcomes are good,” said senior author Anirban Banerjee, MD, FACC, an attending cardiologist with the Cardiac Center at CHOP. “These findings may inform early guidelines for outpatient management strategies and recommendations for returning to competitive sports.”

Learn more about this study here.

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