Cardiac dysfunction in Multisystem Inflammatory Syndrome in Children: An Italian single-center study.

Background: Multisystem inflammatory syndrome in children (MIS-C) is a novel condition temporally associated with SARS-CoV2 infection. Cardiovascular involvement is mainly evident as acute myocardial dysfunction in MIS-C. The aim of this study was to describe the cardiac dysfunction in patients with MIS-C, defining the role of severity in the clinical presentations and outcomes in a single cohort of pediatric patients.

Methods: A single-center retrospective study on patients diagnosed with MIS-C, according to the Center for Disease Control and Prevention (CDC) definition, and referred to Vittore Buzzi Children's Hospital in Milan from November 2020 to February 2021. Patients were managed according to a local approved protocol. According to the admission cardiac left ventricular ejection fraction (LVEF), the patients were divided into group A (LVEF < 45%) and group B (LVEF ≥45%). Pre-existing, clinical, and laboratory factors were assessed for evaluating outcomes at discharge.

Results: Thirty-two patients were considered. Cardiac manifestations of MIS-C were reported in 26 patients (81%). Group A included 10 patients (9 M/1F, aged 13 years [IQR 5-15]), and group B included 22 patients (15 M/7 M, aged 9 years [IQR 7-13]). Significant differences were noted among clinical presentations (shock, diarrhea, intensive care unit admission), laboratory markers (leucocytes, neutrophils, and protein C-reactive), and cardiac markers (troponin T and N-terminal pro B-type Natriuretic Peptide) between the groups, with higher compromission in Group A. We found electrocardiogram anomalies in 14 patients (44%) and rhythm alterations in 3 patients (9%), without differences between groups. Mitral regurgitation and coronary involvement were more prevalent in group A. Total length of hospital stay and cardiac recovery time were not statistically different between groups. A recovery of cardiac functioning was reached in all patients.

Conclusion: Despite significant differences in clinical presentations and need for intensive care, all of the MIS-C patients with significant cardiac involvement in this study completely recovered. This suggests that the heart is an involved organ and did not influence prognosis if properly treated and supported in the acute phase.