What is already known about this subject? Hydroxychloroquine has been used as anti-malarial and anti-rheumatic drug for decades, with only very few reports of cardiac death after use of this drug.The current SARS-Cov-2 pandemic has raised renewed attention on hydroxychloroquine. Concerns were raised on the pro-arrhythmic effects of hydroxychloroquine, that are presumably caused by blockage of the cardiac hERG channel. This study analyzed the effect of hydroxychloroquine, dosed in a regular regimen for SARS-CoV-2 patients, on the ventricular repolarization in a concentration-effect analysis.
What does this study add? There were no significant associations between hydroxychloroquine concentration and ECG characteristics, including QTcF-interval and T-wave morphology, measured with a Morphology Combination Score (MCS). Based on this analysis, hydroxychloroquine does not significantly affect the QTcFinterval and does not significantly increase the risk of arrhythmias in the studied dosing regimen and population. This outcome can be explained by the maximal plasma concentration of this dosing regimen, that is not high enough to exert hERG channel inhibition.