The effects of combined hydroxychloroquine and azithromycin therapy on QRS wave in COVID-19 patients



Arrhythmia, Azithromycin, COVID-19, Electrocardiography, Hydroxychloroquine


Background/Aim: Hydroxychloroquine and azithromycin are frequently used for the treatment of coronavirus disease 2019 (COVID-19). The use of these medications increases the risk of adverse cardiovascular events. The aim of our study was to investigate the effects of these drugs on the arrhythmogenic electrocardiographic (ECG) markers, QRS duration, and QRS dispersion, and also to evaluate gender differences with respect to these effects. Methods: Between March and June 2020, 107 (54 males, 53 females) patients admitted to our hospital’s isolation ward with COVID-19 diagnosis with no history, risk factors, or clinical findings of cardiovascular diseases were included in this prospective cohort study. All participants had a mild illness, and none of them required intensive care unit admission. ECGs of the patients were recorded before starting treatment with combined hydroxychloroquine and azithromycin, and a second ECG was recorded on the next morning following the last dose of the treatment. All ECGs were evaluated by two blinded cardiologists in terms of QRS duration and dispersion. Results: Among study participants, QRS duration was significantly prolonged after treatment with hydroxychloroquine and azithromycin (81.14 (9.11) versus 85.5 (10.48) ms [P < 0.01]), and the same pattern was observed with QRS dispersion (36.67 (9.54) versus 40.18 (9.35) ms [P < 0.01]). When gender differences were evaluated, male patients also showed significant changes in both QRS duration (82.65 (8.04) versus 87.31 (10.7) ms [P < 0.01]), and dispersion (36.93 (8.61) versus 41.31 (9.63) ms [P < 0.01]), while in females the difference was statistically insignificant for both QRS duration (79.06 (10.18) versus 82.8 (9.79) ms [P = 0.056]), and dispersion (36.31 (10.83) versus 38.62 (8.86) ms [P = 0.23]). Conclusions: The combined use of hydroxychloroquine and azithromycin led to an increase in both QRS duration and dispersion in all patients. These changes were more significant in males than in female patients. No clinical effects of these ECG changes were observed in the short-term, and further studies are needed to investigate the possible clinical implications of these drugs during longer follow-up periods.


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Koçak A, Coşgun A, Karamanlıoğlu D, Türkkanı MH. The effects of combined hydroxychloroquine and azithromycin therapy on QRS wave in COVID-19 patients. J Surg Med [Internet]. 2022 Apr. 1 [cited 2024 Jul. 15];6(4):483-7. Available from: