Conclusion
HCQ use in COVID-19 may cause a significant proportion of critical QTc prolongation. In our study population, DM and concomitant oseltamivir use were found to raise the incidence of critical QTc prolongation but none of our patients suffered from TdP, ventricular arrhythmia and sudden cardiac arrest. Because of the nature of COVID-19, the use of concurrent drugs and the clinical situations that have potential to enhance QTc interval should be kept in mind while using HCQ and special attention should be paid for ECG monitoring.