Baseline NT-proBNP level was significantly correlated with indices of the severity of COVID-19, including respiratory rate (r = 0.158; p = 0.026) and oxygen saturation (SpO2) (r = −0.450; p < 0.001), and parameters of inflammation: hs-CRP H1 (r = 0.190; p = 0.015), neutrophil count (r = 0.287; p = −0.016), and lymphocyte count (r = −0.187; p = 0.016) as well as hs-cTnT (r = 0.391; p < 0.001) and D-dimers H1 (r = 0.301; p < 0.001). The gene discussed is TNNT2; the disease is COVID-19.