Interleukin-6 is upregulated and may be associated with myocardial injury in some patients who have recovered from COVID-19.

Coronavirus disease (COVID-19) causes myocardial injury by inducing a cytokine storm in severe cases. Studies have reported that myocardial injury persists for a prolonged period during COVID-19 recovery, and cardiac troponin is a useful indicator of myocardial injury. The interleukin-6 (IL-6) level is known to be associated with the morbidity and mortality of COVID-19, but this association has not been studied during recovery. The current study examined the association between IL-6 levels and myocardial damage during COVID-19 recovery. Four of 209 patients (1.9%) who recovered from COVID-19 had elevated IL-6 levels. All 4 patients tested positive for high-sensitivity troponin T, and 3 patients had subclinical left ventricular (LV) dysfunction according to echocardiography. Positivity for IL-6 during COVID-19 recovery suggests ongoing myocardial damage due to inflammation.