Cardiac Manifestations of Multisystem Inflammatory Syndrome in Iranian Children (MIS-C) Associated with COVID-19; Incidence and One-Year Follow-up

Abstract

Background: Multisystem inflammatory syndrome in children (MIS-C) is a clinical condition involving fever, multi-system organ dysfunction, and an increase in inflammatory biomarkers. Objectives: This cross-sectional study was carried out to assess the clinical presentations and cardiac involvement in MIS-C. Methods: This study was conducted in a referral pediatric hospital in Iran, from March 2020 to December 2022, in patients with MIS-C according to the Centers for Disease Control and Prevention (CDC) definition. Cardiac involvement was checked through echocardiography and electrocardiography (ECG). All patients were followed up for one year. The results were analyzed, and a P-value of < 0.05 was considered significant. Results: Out of 200 MIS-C patients, 48 (24%) had cardiac involvement, among which decreased left ventricle ejection fraction (LVEF), coronary disorders, mitral regurgitation, pericardial effusion, and cardiogenic shock were found in 20 (41.6%), 8 (16.6%), 16 (33.3%), 22 (45.8%), and 8 (16.6%), respectively. In all 200 cases, 59 had ECG abnormalities, and some were without cardiac involvement. Comparing laboratory findings in two groups — those with cardiac involvement and those with a normal heart — significance was seen in counts of WBC, lymphocytes, platelets, and the levels of troponin I and D-dimer. The results of RT-PCR for COVID-19 showed significance, but no significance was found for neutrophil count, the level of hemoglobin, and C-reactive protein (CRP). Conclusions: Cardiac involvement in all components was less in our cases, possibly due to genetic background or related to the early use of intravenous immunoglobulin (IVIG) and corticosteroids. The most common cardiac manifestations were reduced LVEF, pericardial effusion, and electrocardiogram abnormalities. Increased troponin I and D-dimer and thrombocytosis seem to be good predictors for cardiovascular involvement, and one-year follow-up showed a good prognosis.