Hydroxychloroquine/azithromycin treatment, QT interval and ventricular arrhythmias in hospitalised patients with COVID-19

Int J Clin Pract. 2021 Feb;75(2):e13896. doi: 10.1111/ijcp.13896. Epub 2020 Dec 15.


Background: Hydroxychloroquine (HCQ) and azithromycin (AZM) are widely used in off-label treatment of novel coronavirus disease (COVID-19). However, cardiac safety of these drugs is still controversial in COVID-19. Therefore, we aimed to evaluate association of HCQ or HCQ + AZM treatment regimens, corrected QT (QTc) interval and malignant ventricular arrhythmias in hospitalized patients.

Methods: This is a single-center, retrospective and observational study. All data were extracted from the electronic medical records. The initial and post-treatment mean QTc intervals were calculated and compared in patients with HCQ alone or HCQ + AZM therapy. Associated factors with QTc prolongation, the incidence of ventricular arrhythmia during treatment and in-hospital mortality because of ventricular arrhythmias were evaluated.

Results: Our cohort comprised 101 hospitalized COVID-19 patients (mean age of 49.60 ± 18 years, 54.4% men). HCQ + AZM combination therapy group (n = 56) was more likely to have comorbidities. After 5-days treatment, 19 (18.8%) patients had QTc prolongation, and significant increase in the QTc interval was observed in both two groups (P < .001). However, HCQ + AZM combination group had significantly higher ΔQTc compared to HCQ group (22.5 ± 18.4 vs 7.5 ± 15.3 ms, P < .001). All of 101 patients completed the 5-days treatment without interruption. Also, no malignant ventricular arrhythmia or death secondary to ventricular arrhythmia occurred during the treatment in both groups.

Conclusions: The present study revealed that although HCQ + AZM treatment was independently associated with QTc prolongation, none of patients experienced malignant ventricular arrhythmia or death during treatment. Further prospective studies are needed to determine the exact implications of these drugs on arrhythmias in patients with COVID-19.

Publication types

  • Observational Study

MeSH terms

  • Adult
  • Aged
  • Anti-Bacterial Agents / therapeutic use*
  • Arrhythmias, Cardiac / drug therapy*
  • Arrhythmias, Cardiac / epidemiology
  • Azithromycin / therapeutic use*
  • COVID-19 / epidemiology
  • COVID-19 Drug Treatment*
  • Comorbidity
  • Drug Therapy, Combination
  • Electrocardiography
  • Female
  • Humans
  • Hydroxychloroquine / therapeutic use*
  • Long QT Syndrome / drug therapy*
  • Long QT Syndrome / epidemiology
  • Male
  • Middle Aged
  • Retrospective Studies
  • SARS-CoV-2


  • Anti-Bacterial Agents
  • Hydroxychloroquine
  • Azithromycin