<p><strong>BACKGROUND: </strong>Centers from Europe and United States have reported an exceedingly high number of children with a severe inflammatory syndrome in the setting of COVID-19, which has been termed multisystem inflammatory syndrome in children (MIS-C).</p>

<p><strong>OBJECTIVES: </strong>This study aimed to analyze echocardiographic manifestations in MIS-C.</p>

<p><strong>METHODS: </strong>We retrospectively reviewed 28 MIS-C, 20 healthy controls and 20 classic Kawasaki disease (KD) patients. We reviewed echocardiographic parameters in acute phase of MIS-C and KD groups, and during subacute period in MIS-C group (interval: 5.2 ± 3 days).</p>

<p><strong>RESULTS: </strong>Only 1 case in MIS-C (4%) manifested coronary artery dilatation (z score=3.15) in acute phase, showing resolution during early follow up. Left ventricular (LV) systolic and diastolic function measured by deformation parameters, were worse in MIS-C compared to KD. Moreover, MIS-C patients with myocardial injury (+) were more affected than myocardial injury (-) MIS-C with respect to all functional parameters. The strongest parameters to predict myocardial injury in MIS-C were global longitudinal strain (GLS), global circumferential strain (GCS), peak left atrial strain (LAS) and peak longitudinal strain of right ventricular free wall (RVFWLS) (Odds ratio: 1.45 (1.08-1.95), 1.39 (1.04-1.88), 0.84 (0.73-0.96), 1.59 (1.09-2.34) respectively). The preserved LVEF group in MIS-C showed diastolic dysfunction. During subacute period, LVEF returned to normal (median: from 54% to 64%, p&lt;0.001) but diastolic dysfunction persisted.</p>

<p><strong>CONCLUSIONS: </strong>Unlike classic KD, coronary arteries may be spared in early MIS-C, however, myocardial injury is common. Even preserved EF patients showed subtle changes in myocardial deformation, suggesting subclinical myocardial injury. During an abbreviated follow-up, there was good recovery of systolic function but persistence of diastolic dysfunction and no coronary aneurysms.</p>

<p><strong>CONDENSED ABSTRACT: </strong>Multisystem inflammatory syndrome in children (MIS-C) is an illness that resembles Kawasaki Disease (KD) or toxic shock, reported in children with a recent history of COVID-19 infection. This study analyzed echocardiographic manifestations of this illness. In our cohort of 28 MIS-C patients, left ventricular systolic and diastolic function were worse than in classic KD. These functional parameters correlated with biomarkers of myocardial injury. However, coronary arteries were typically spared. The strongest predictors of myocardial injury were global longitudinal strain, right ventricular strain, and left atrial strain. During subacute period, there was good recovery of systolic function, but diastolic dysfunction persisted.</p>