Cardiac biomarkers comparison between acute myocarditis/myopericarditis and multisystem inflammatory syndrome in children

Objectives: Acute myocarditis/myopericarditis is a heterogeneous disorder of unknown origin, the viral etiology leading the first row. There could be also myocardial involvement in multisystem inflammatory syndrome in children (MIS-C). In this study, we aimed to investigate cardiac biomarkers of acute myocarditis/myopericarditis and MIS-C and to compare these parameters between the two diseases. Methods: Patients who are diagnosed with MIS-C, isolated viral myocarditis/myopericarditis at a university hospital from October 2021 to March 2023 are included in this study. Results: There were 38 MIS-C patients and 53 patients with myocarditis/myopericarditis. The mean age was 141.2 ± 38.2 months (4 to 18 years old) in MISC, and 145.8 ± 52.1 months (7 to 18 years old) in myocarditis/myopericarditis. Median troponin I level was 145 ng/L in MIS-C patients and it was 901 ng/L in myocarditis/myopericarditis patients. Creatinine kinase-myocardial band (CK-MB) median was 2.25 ng/mL (0.6-6.3) versus 6.7 ng/mL in MIS-C and myocarditis/myopericarditis, respectively. Pro Brain natriuretic peptide (Pro-BNP) median level was 2714.5 pg/mL (<300) in MIS-C, and it was 294 in patients with myocarditis/myopericarditis. Troponin I, CK-MB was significantly higher in myocarditis/myopericarditis, while Pro-BNP was significantly higher in MIS-C patients (p < 0.05). The separating power of CK-MB, troponin I, and Pro-BNP level was significantly higher in the differential diagnosis of these two group patients (p < 0.001). MIS-C patients with high pro-BNP levels had more prolonged hospitalization and left ventricular function impairment according to myocarditis/myopericarditis. Conclusions: Cardiac biomarkers (CK-MB, troponin I, and Pro-BNP) could be good markers to estimate the course of the diseases.