Diagnostic and pharmacological correction of cardiovascular system changes in children, adolescents, and young adults with long COVID: comparative randomized clinical trial in parallel groups

The aim. To evaluate the effectiveness of L-carnitine in the complex correction of cardiovascular and autonomic manifestations of long COVID in children, adolescents, and young adults. Materials and methods. Within the framework of an open, simple, randomized, parallel-group comparative clinical study, the effectiveness of L-carnitine at a dose of 50–75 mg/kg per day in 2 doses for 6 weeks in addition to standard therapy in children and adolescents aged 10 to 17 years, as well as young people aged 18–25 years with long COVID ( n = 45) was studied in comparison with the standard therapy ( n = 45) using clinical and anamnestic, electrophysiological, echocardiographic and other methods. The statistical processing of the results was carried out by the variational method, and correlation and regression analysis using Student’s t -test for dependent samples, as well as the McNemar chi-square test. Results . The most frequent clinical manifestations of long COVID were: high fatigue, headaches and muscle weakness — in 66.7–100%. After 6 weeks of treatment, the absence of complaints and normalization of objective status were noted in 93.3% of patients in the main group and 66.7% in the comparison group ( p < 0.05). Repolarization abnormalities and rhythm disturbances, initially registered in 43.3% of patients, were not observed after 6 weeks of therapy in the main group, while they persisted in more than 50% in the comparison group. By the 6 weeks of treatment, there were no changes in Echo in the main group, while in the comparison group (slight dilatation of the left ventricle) persisted in 9 out of 12 patients. In the main group, according to Holter monitoring, restoration of heart rate, normalization of its autonomic regulation, reduction in the representation of bradyarrhythmias and “density” of extrasystoles were achieved. Conclusion. The effectiveness of L-carnitine for the correction of the frequency and severity of autonomic and cardiac disorders in the subjects with long COVID has been shown.