Assessment of Repeated Electrocardiogram Findings in Pediatric Multisystem Inflammatory Syndrome Associated with COVID-19

Background: Cardiac involvement, stemming from the novel multisystem inflammatory syndrome in children (MIS-C) associated with coronavirus disease-2019 (COVID-19), leads to common and severe complications. Objectives: The aim of this study is to compare and evaluate repetitive electrocardiogram (ECG) results and laboratory indicators in children diagnosed with MIS-C upon their initial hospital admission. Methods: This prospective, single-center study, conducted between December 2020 and October 2022, included repeated electrocardiographic and laboratory tests. Changes in the ECG over the course of the disease were regularly recorded for three months. Results: This study included 72 patients, 25 of whom were female. Mitral regurgitation and left ventricular systolic dysfunction were observed in 25% of the patients. Statistically significant differences (P < 0.05) were detected among the serial measurements of absolute neutrophil-lymphocyte count, CRP, procalcitonin, ESR, D-dimer, troponin T, pro-BNP, ferritin, and interleukin-6. Significant differences were also observed in heart rate, PR interval, QRS duration, QT duration, Fredericia QTc, JT interval, presence of sinus tachycardia, presence of first-degree AV block, presence of wide QRS, abnormal QRS axis, abnormal T axis, long QTc, and ST-T changes (P < 0.05). Additionally, significant differences were noted in the absolute lymphocyte count, troponin levels, and ferritin levels between patients with prolonged abnormal ECG findings and those whose ECG findings were normal or had returned to normal. Furthermore, statistically significant differences were observed in absolute lymphocyte count, ferritin, and fibrinogen levels among the other four groups (P < 0.05). Conclusions: Electrocardiogram findings in patients measured serially appear to improve over time. Since patients with MIS-C may experience ECG abnormalities that could lead to arrhythmias, close monitoring and the establishment of standardized approaches are essential. Long-term ECG abnormalities were associated with a decrease in absolute lymphocyte count and elevated levels of troponin, ferritin, and fibrinogen.