Cardiovascular abnormalities in Multisystem Inflammatory Syndrome in Children (MISC) related to COVID-19

Nathalie Jeanne M Bravo-Valenzuela^1,2*Thiago Taucei Panizzi¹Katharine Aguiar¹Stutz Blanco Gabriela¹Rafaela Vieira Meirelles Aurelio¹Marta Felix Felix Rodrigues¹Rozana Gasparello de Almeida¹Fernanda Maria Correia Ferreira Lemos¹Alan de Lima Araujo¹Flavio Sztajnbok¹Adriana Rodrigues Fonseca¹

• ¹Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
• ²Instituto de Cardiologia, Porto Alegre, Brazil

Introduction: The COVID-19 pandemic began with the identification of SARS-CoV-2 in December 2019. Although children usually have milder acute symptoms, they can develop severe systemic symptoms termed pediatric multisystem inflammatory syndrome (MIS-C). This study reviews research in children and adolescents diagnosed with MIS-C, focusing on cardiovascular abnormalities. Methodology: This systematic review was conducted following PRISMA guidelines. The review protocol was prospectively registered in the Prospective Register of Systematic Reviews (PROSPERO; registration number: CDR420251232497). A search strategy was constructed to identify the studies focusing on cardiovascular abnormalities in children and adolescents with MIS-C published in Portuguese and English at PubMed and Scielo from January 2020 to February 2025. The eligibility criteria and data extraction strategy were guided by the PICO framework. Conclusions: Myocardial dysfunction and coronary abnormalities are the most frequent cardiovascular features in patients with MIS-C. Strain technology in echocardiography identifies early myocardial dysfunction, with studies showing persistent subclinical injuries. Despite ejection fraction and coronary anomalies returning to normal short to medium term, long-term cardiovascular effects of MIS-C remain uncertain, necessitating ongoing cardiology monitoring.