Arrhythmic safety of hydroxychloroquine in COVID-19 patients from different clinical settings

Alessio Gasperetti, Mauro Biffi, Firat Duru, Marco Schiavone, Matteo Ziacchi, Gianfranco Mitacchione, Carlo Lavalle, Ardan Saguner, Antonio Lanfranchi, Giacomo Casalini, Marco Tocci, Davide Fabbricatore, Francesca Salghetti, Marco Valerio Mariani, Mattia Busana, Alfonso Bellia, Chiara Beatrice Cogliati, Pierluigi Viale, Spinello Antinori, Massimo GalliNazzareno Galiè, Claudio Tondo, Giovanni Battista Forleo

Research output: Contribution to journalArticlepeer-review


AIMS: The aim of the study was to describe ECG modifications and arrhythmic events in COVID-19 patients undergoing hydroxychloroquine (HCQ) therapy in different clinical settings. METHODS AND RESULTS: COVID-19 patients at seven institutions receiving HCQ therapy from whom a baseline and at least one ECG at 48+ h were available were enrolled in the study. QT/QTc prolongation, QT-associated and QT-independent arrhythmic events, arrhythmic mortality, and overall mortality during HCQ therapy were assessed. A total of 649 COVID-19 patients (61.9 ± 18.7 years, 46.1% males) were enrolled. HCQ therapy was administrated as a home therapy regimen in 126 (19.4%) patients, and as an in-hospital-treatment to 495 (76.3%) hospitalized and 28 (4.3%) intensive care unit (ICU) patients. At 36-72 and at 96+ h after the first HCQ dose, 358 and 404 ECGs were obtained, respectively. A significant QT/QTc interval prolongation was observed (P < 0.001), but the magnitude of the increase was modest [+13 (9-16) ms]. Baseline QT/QTc length and presence of fever (P = 0.001) at admission represented the most important determinants of QT/QTc prolongation. No arrhythmic-related deaths were reported. The overall major ventricular arrhythmia rate was low (1.1%), with all events found not to be related to QT or HCQ therapy at a centralized event evaluation. No differences in QT/QTc prolongation and QT-related arrhythmias were observed across different clinical settings, with non-QT-related arrhythmias being more common in the intensive care setting. CONCLUSION: HCQ administration is safe for a short-term treatment for patients with COVID-19 infection regardless of the clinical setting of delivery, causing only modest QTc prolongation and no directly attributable arrhythmic deaths.


  • Arrhythmias
  • COVID-19
  • Hydroxychloroquine
  • QT interval
  • SARS-CoV-2

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)


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