Cardiac function returns to normal within three months in children with MIS-C associated with Covid-19, according to a new study reported in the Journal of the American Heart Association.

This study included 60 children, average age 10 years, who had been hospitalized with MIS-C after Covid infection between April 2020 and January 2021. Sixty children, with no Covid exposure or MIS-C or any structural heart disease were also enrolled as the control group. The study group was analyzed with the aim to assess the cardiac outcomes 3 to 4 months after initial presentation and to determine the short‐term impact of acute myocardial injury caused by MIS‐C with the help of conventional echocardiography, speckle tracking echocardiography and cardiac magnetic resonance imaging (MRI). Data analysis was done at the time of the hospitalization (acute phase), one week after the first echocardiography (subacute phase), at one-month follow-up and at 3-4 month follow-up. Acute myocardial injury was defined by a 3-folds increase in levels of troponin I (≥0.09 ng/mL) or raised brain‐type natriuretic peptide (BNP) >800 pg/mL

Improvement in systolic and diastolic function in the left ventricle and systolic function in the right ventricle was noted in the first week. And this trend continued leading to complete normalization of function by three months.

Loss of function of the left ventricle in the acute was observed in 81% of children, but this too normalized by 3-4 months.

Seventy percent of MIS-C patients had some evidence of some myocardial injury at the time of initial presentation, however, all scans were normal at 3 months. MIS-C did not result in long-term coronary artery abnormalities.

There was no subclinical dysfunction after 3 months as evident by complete normalization of all strain parameters used to evaluate cardiac function such as left ventricular global longitudinal strain, peak left atrial strain, longitudinal early diastolic strain rate, right ventricular free wall strain.

Four patients (7%) had small coronary aneurysms at presentation, all of which resolved. Only one patient showed residual edema on follow-up cardiac MRI. However, there was no evidence of fibrosis and systolic function were normal on echocardiography.

Evaluation of impact on heart in children with MISC-C following Covid-19 with regard to any structural deformity or changes in function using strain imaging in this short-term study demonstrated resolution of cardiac function with no residual subclinical cardiac dysfunction at 3 months. A follow-up cardiac MRI can be done in children who have had abnormal cardiac MRI at baseline during the acute stage.

These findings are reassuring and show that myocardial involvement in these patients is transient in nature allowing return to normal physical activity or sports. Possibly there may not be any long-lasting impact on cardiac function. However, a long-term study is required to corroborate these observations. According to the study authors, “these findings may provide early guidelines for outpatient management strategies and recommendations for returning to competitive sports after 3 months.”

 Reference

1. Daisuke Matsubara, et al. Longitudinal assessment of cardiac outcomes of multisystem inflammatory syndrome in children associated with COVID-19 Infections. J Am Heart Assoc. 2022 Jan 19;e023251. doi: 10.1161/JAHA.121.023251.