Differences Between Pediatric Acute Myocarditis Related and Unrelated to SARS-CoV-2

BACKGROUND: Acute myocarditis (AM) is defined as inflammation of the myocardium. The aim of our study is a comparative analysis of the differences between AM related and unrelated to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). METHODS: The retrospective study included children with AM treated from January 2018 to November 2020. RESULTS: The study included 24 patients; 7 of 24 had AM related to SARS-CoV-2 and they were older than 7. They were more likely to have abdominal pain (P = 0.014), headache (P = 0.003), cutaneous rash (P = 0.003), and conjunctivitis (P = 0.003), while fulminant myocarditis was commonly registered in AM unrelated to SARS-CoV-2 (P = 0.04). A multisystem inflammatory syndrome in children associated with COVID-19 was diagnosed in six adolescents. Patients with AM related SARS-CoV-2 had lower serum cardiac troponin I (cTnI) (P = 0.012), and platelets (P < 0.001), but had a higher C-reactive protein (CRP) value (P = 0.04), and N-terminal-pro hormone BNP in comparison to patients with AM unrelated to SARS-CoV-2. The patients with AM related to SARS-CoV-2 had significant reduction of CRP (P = 0.007). Inotropic drug support was used for shorter durations in patients with AM related to SARS-CoV-2, than in others (P = 0.02). Children with AM related to SARS-CoV-2 had significant improvement of left ventricle systolic function on the third day in hospital (P = 0.001). Patients with AM unrelated to SARS-CoV-2 AM had more frequent adverse outcomes (P = 0.04; three died and four dilated cardiomyopathy). CONCLUSIONS: In contrast to patients with AM unrelated to SARS-CoV-2, patients with AM related to SARS-CoV-2 had a higher CRP value, polymorphic clinical presentation, shorter durations of inotropic drugs use as well as prompt recovery of left ventricle systolic function.