ABSTRACT
Introduction: Many antiviral agents such as hydroxychloroquine have been studied to treat COVID-19, without being broadly accepted. Multiple side effects have been described, with QTc interval prolongation being one of the most worrisome. Literature on electrocardiographic alterations in COVID-19 is scarce. There aren't large samples of paediatric patients receiving hydroxychloroquine beyond Covid-19 to establish its relationship with electrocardiographic abnormalities. This study aims to describe QTc prolongation in relation to hydroxychloroquine and its association with other antivirals: lopinavir/ritonavir, remdesivir and azithromycin. Methods: COVID-19 cases were detected by Polymerase Chain Reaction from nasopharyngeal aspirate and matched at a 1:2 ratio according to age and sex with controls not exposed to study drugs nor infected by COVID-19. Electrocardiograms, collected S62 Cardiology in the Young: Volume 32 Supplement 1 prospectively, were evaluated manually by the same person. QT intervals were calculated in 3 different beats and corrected with the Bazett formula. Electrocardiographic cut-off points were determined: before treatment, within 72 hours of the start and after more than 72 hours. Data were compared by using oneway ANOVA. Results: 11 out of 48 paediatric patients admitted due to COVID- 19 from March to July 2020, received antiviral therapy (22.9%) based on clinical evidence at the time;median age 9 years (IQR 10.5), 54.5% were male. Among the main underlying pathologies, congenital heart diseases (36.4%) and malignant haematological diseases (27.3%) stood out;5 had received treatments potentially causing QTc prolongation. 10 patients (90.9%) received hydroxychloroquine, mostly in association with azithromycin (80%). 3 patients received lopinavir/ritonavir and one remdesivir. The mean of the baseline QTc interval was 418.5ms (407.4-429.6, 95%CI), before 72 hours was 424.6ms (398.1-451.2). A prolongation occurred after 72 hours: 439.7ms (408.5-470.9) but was not significant (p=0.253). 2 patients had long QTc interval before starting the treatment, and 4 after 72 hours. No patient presented arrhythmias. Conclusions: A small proportion of patients received antiviral drugs. All had underlying diseases and a great proportion were taking drugs with an effect on QTc interval;this could contribute to QTc prolong. QTc prolongation occurred after 72 hours under treatment. Although only one patient had a QTc interval longer than 500ms (treatment was stopped afterwards) and none presented arrhythmias, QTc monitoring is advised.