© Copyright 2021 by Turkish Society of Cardiology - Available online at www.anatoljcardiol.comObjective: Cytokine storm with elevated levels of multiple proinflammatory cytokines and inflammatory system activation underlie the pathogenesis of coronavirus disease 2019 (COVID-19). In this study, we aimed to investigate whether increased interleukin (IL)-6 levels can predict right ventricular (RV) systolic impairment in patients hospitalized with COVID-19. Methods: This prospective, observational study included 100 consecutive patients hospitalized with mild and moderate COVID-19. All the patients underwent chest computerized tomography, detailed laboratory tests including IL-6, and two dimensional (2D) transthoracic echocardiography (TTE) with assessment of 2D conventional and Doppler echocardiography parameters and RV systolic functions. Results: After the elimination of six patients with exclusion criteria, the remaining patients were classified into two groups, namely normal RV systolic functions (n=60) and impaired RV systolic functions (n=34). IL-6 levels were significantly higher in patients with impaired RV systolic functions than in those with normal RV systolic functions (20.3, 4.6, p<0.001, respectively). Tricuspid annular plane systolic excursion and RV derived tissue Doppler imaging (TDI) S' measurements were similar between the two groups. RV fractional area change was significantly lower, and RV TDI derived index of myocardial performance was significantly higher in patients with impaired RV systolic functions. In multivariate analysis, IL-6 levels independently predicted deterioration in RV systolic function at a significant level (odds ratio: 1.12, 95% confidence interval: 1.04-1.20, p=0.003). Conclusion: IL-6 is an independent predictor of RV systolic impairment in patients hospitalized with mild and moderate COVID-19 suggesting a possible pathogenetic mechanism. IL-6 levels can be used to predict RV systolic impairment in patients suffering from this infection.