Cardiac effects of multisystem inflammatory syndrome in children: One-year follow-up.

Aim: Cardiovascular involvement is common among children with multisystem inflammatory syndrome (MIS-C) and can cause shock and death. In this study, we evaluated the early and long-term cardiac effects of MIS-C.

Methods: In this observational cohort study, we included all children treated for MIS-C from October 2020 to November 2021 in the Department of Paediatric Infectious Disease at Cukurova University School of Medicine Hospital. The patients underwent serial echocardiographical evaluation during hospitalisation and at 1, 3, 6 and 12 months after discharge. The patients were evaluated using Holter monitorisation between 4 and 6 months and using cardiac magnetic resonance imaging at 6 months and thereafter.

Results: Twenty-six patients diagnosed with MIS-C and with a median age of 84 months were included. Cardiac involvement was found in 19 (73.1%) patients. At initial echocardiographic evaluation, the mean ejection fraction value of the patients was 56.7% (range: 30-75). Coronary artery dilatation was detected in two (7.7%) patients, and mitral regurgitation persisted in only one patient by month 3. Treatment was started in two (7.7%) patients due to ventricular arrhythmia. Cardiac magnetic resonance imaging was performed in 13 (50%) patients at a median of 6 months (range: 5-9). The cardiac magnetic resonance imaging findings were consistent with possible interstitial fibrosis in two (7.7%) patients.

Conclusion: Our results showed that cardiac involvement of patients improved rapidly with treatment, as indicated by previous studies. However, during the 1-year follow-up, frequent extraventricular systole was detected in two patients, one of whom initially did not show cardiac involvement. Moreover, possible interstitial fibrosis was detected in the cardiac magnetic resonance imaging (MRI) evaluation of two patients. In particular, we believe that these findings may be useful to evaluate critically ill paediatric patients and patients with severely low EF with cardiac MRI in their follow-up.