Acute QT Interval Modifications During Hydroxychloroquine-Azithromycin Treatment in the Context of COVID-19 Infection

Among candidate drugs to treat coronavirus disease 2019 (COVID-19), the combination of hydroxychloroquine (HCQ) and azithromycin (AZ) has received intense worldwide attention. Even as the efficacy of this combination is under evaluation, clinicians have begun to use it largely. As these medications are known to prolong the QT interval, we analyzed serial electrocardiograms recorded in patients hospitalized for COVID-19 pneumonia and treated with HCQ + AZ. Fifty consecutive patients received the combination of HCQ (600 mg/d for 10 days) and AZ (500 mg/d on day 1 and 250 mg/d from day 2 to day 5). Twelve-lead electrocardiograms were recorded before treatment, at day 3, at day 5, and at discharge. The median age of patients was 68 years (interquartile range, 53-81 years); 28 (56%) were men. The main comorbidities were hypertension (36%; n=18) and diabetes (16%; n=8). The mean corrected QT (QTc) interval was 408 ms at baseline and increased up to 437 ms at day 3 and to 456 ms at day 5. Thirty-eight patients (76%) presented short-term modifications of the QTc duration (>30 ms). Treatment discontinuation was decided in 6 patients (12%), leading to QTc normalization in 5 of them. No deaths and no cardiac arrhythmic events were observed in this cohort. Our report confirms that a short duration treatment with HCQ + AZ modifies the QTc interval. The treatment had to be discontinued for QTc modifications in 12% of patients. Nevertheless, in inpatients hospitalized for COVID-19, we did not observe any clinically relevant consequences of these transitory modifications. In conclusion, when patients are treated with HCQ + AZ, cardiac monitoring should be regularly performed and hospital settings allow monitoring under in safe conditions.