Thus, we investigated: (1) the QTc duration in patients with COVID-19 during the active phase and recovery, and its association with CRP and IL-6 levels; (2) the acute impact of IL-6 administration on QTc in an in vivo guinea pig model; and (3) the electrophysiological effects of IL-6 on ventricular myocytes in vitro. The gene discussed is CRP; the disease is COVID-19.