Late-Term Cardiac Magnetic Resonance Imaging in Multisystem Inflammatory Syndrome in Children

Multisystem inflammatory syndrome in children (MIS-C) develops as an exaggerated, complex, postinfectious immune response related to severe acute respiratory syndrome coronavirus (SARS-CoV-2 virus), which affects all systems in the body. Cardiac involvement in children can have a spectrum ranging from mild disease to severe heart failure due to fulminant myocarditis. Cardiac involvement usually resolves after clinical recovery. However, the adverse effect of myocarditis on cardiac function after recovery is not fully known. In this study, we aimed to investigate cardiac involvement by performing cardiac magnetic resonance imaging (MRI) after acute and recovery stage. Here, we describe the clinical and laboratory features and the effect of treatment on the development of fibrosis on cardiac MRI in 21 patients with MIS-C and the localization of fibrosis in five patients.When compared with 16 patients with normal cardiac MRI, five patients with cardiac fibrosis on MRI had a greater age (mean 14.4 ± 4.0 years vs 8.9 ± 3.5 years; p=0.007), a similar gender distribution (male/female: 3/2 vs 5/11; p= 0.325), a greater body mass index (BMI) (mean 22.68±4.48 kg/m2 vs 17.73±3.15 kg/m2;p=0.012), a lower leucocyte count, [median 5250/μl (3880-7790) vs 12065/μl (4210-21210); p=0.011], a lower neutrophil count [median 4000/μl (2150-6560) vs 9875/μl (2540-18500); p=0.019], a higher blood urea nitrogen level [median 15 mg/dL (11-26.8) vs 8.5 mg/dL (4-18); p=0.025], and a higher creatinine level (mean 0.61±0.07 mg/dL vs 0.45±0.14 mg/dL; p= 0.024). Cardiac fibrosis on MRI was located in the region of posterior right ventricle insertion point and in the midventricular septum.ConclusionsAdolescence and obesity appear as risk factors for the development of fibrosis as a late-term sequela of myocarditis. We believe that other mechanisms such as a complex immune system response and hemodynamic instability causing acute kidney injury may similarly play a role for the development of cardiac fibrosis. However, this subject should be clarified by more comprehensive studies. Furthermore, future studies reporting the follow-up data of patients with fibrosis are necessary to predict and manage adverse outcomes.