QT prolongation associated with azithromycin/hydroxychloroquine combination in treatment of COVID-19: a single centre study

Background: The long QT syndrome is characterized by prolongation of QT interval, which may lead to life-threatening cardiac arrhythmias. Objectives were to assess prevalence, quantity and severity of QTc prolongation with combined drugs (azithromycin and hydroxychloroquine) in adults COVID-19 patients treated on these agents at KFSHRC. And to characterize cardiac complications of QTc prolongation with combined drugs. Methods: A retrospective cohort study at KFSHR QT range was 472-475, hydroxychloroquine was stopped on day 4. None of them had torsades de pointes. Only one patient with low risk, no baseline QT was recorded, but QT was 499 on day three, so hydroxychloroquine was stopped. Repeated ECG showed: QT decreased to 478, no torsades de pointes. Conclusions: In this single centered-retrospective cohort, we noticed that a small percentage of patients developed QT prolongation with the use of this combination. With the increasing the risk of developing QT prolongation the number of the patient who developed the condition increased. We used Tisdale score which is a scoring system Identifying hospitalized patients at risk for QT interval prolongation could lead to interventions to reduce the risk of torsades de pointes validated in May 2013.5 None of our population developed significant cardiac complications of QTc prolongation with combined drugs.