Strain in children with MIS-C and acute COVID-19

Cardiac injury has been described in both acute COVID-19 and the multisystem inflammatory syndrome in children (MIS-C). Echocardiographic strain has been shown to be a sensitive measure of systolic function.

We sought to describe strain findings in both the groups on initial presentation and follow-up.

A retrospective study analyzing echocardiograms of all patients presenting with acute COVID-19 infection and MIS-C at our institution between March 2020 and December 2020 was performed.

TOMTEC software was used for strain analysis in both the study groups (COVID-19 and MIS-C) and age-matched healthy controls. Strain was correlated with LV ejection fraction (EF) and serum troponin levels.

Forty-five patients (34 - MIS-C and 11 - COVID-19) met the inclusion criteria. There was a statistically significant decrease in LV longitudinal strain (P < 0.001), LV circumferential strain (P < 0.001), and left atrial strain (P = 0.014) in the MIS-C group when compared to the control group. There was a statistically significant decrease in LV longitudinal strain (P = 0.028) in the acute COVID-19 group. All patients with abnormal left ventricular EF (LVEF) had abnormal strain. However, 14 (41%) patients in the MIS-C group and 3 (27%) in the acute COVID-19 group had preserved LVEF but abnormal strain. There was a significant correlation with LV longitudinal strain (P = 0.005) and LVEF (P = 0.002) and troponin in patients with MIS-C. Abnormal strain persisted in one-third of patients in the MIS-C and acute COVID-19 groups on outpatient follow-up.

Patients with MIS-C and acute COVID-19 can develop myocardial dysfunction as seen by abnormal strain. LV longitudinal strain correlates with cardiac injury as measured by serum troponin in patients with MIS-C. Strain may provide an additional tool in detecting subtle myocardial dysfunction. It can be routinely employed at diagnosis and at follow-up evaluation of these patients.