Cardiac injury is common in severe coronavirus disease 2019 (COVID-19) and is associated
with poor outcomes. We aimed to study predictors of in-hospital death, characteristics
of arrhythmias and the effects of QT-prolonging therapy in patients with cardiac injury.
We conducted a retrospective cohort study involving patients with severe COVID-19
who were admitted to Tongji Hospital in Wuhan, China, between Jan. 29 and Mar. 8,
2020. Among patients who had cardiac injury, which we defined as an elevated level
of cardiac troponin I (cTnI), we identified demographic and clinical characteristics
associated with mortality and need for invasive ventilation. Among 1284 patients with
severe COVID-19, 1159 had a cTnI level measured on admission to hospital, of whom
170 (14.7%) had results that showed cardiac injury. We found that mortality was markedly
higher in patients with cardiac injury (71.2% v. 6.6%, p < 0.001). We determined
that initial cTnI (per 10-fold increase, hazard ratio [HR] 1.32, 95% confidence interval
[CI] 1.06–1.66) and peak cTnI level during illness (per 10-fold increase, HR 1.70,
95% CI 1.38–2.10) were associated with poor survival. Peak cTnI was also associated
with the need for invasive ventilation (odds ratio 3.02, 95% CI 1.92–4.98). We found
arrhythmias in 44 of the 170 patients with cardiac injury (25.9%), including 6 patients
with ventricular tachycardia or fibrillation, all of whom died. We determined that
patients who received QT-prolonging drugs had longer QTc intervals than those who
did not receive them (difference in medians, 45 ms, p = 0.01), but such treatment
was not independently associated with mortality (HR 1.04, 95% CI 0.69–1.57). We found
that in patients with COVID-19 and cardiac injury, initial and peak cTnI levels were
associated with poor survival, and peak cTnI was a predictor of need for invasive
ventilation. Patients with COVID-19 warrant assessment for cardiac injury and monitoring,
especially if therapy that can prolong repolarization is started. Chinese Clinical
Trial Registry, No. ChiCTR2000031301.