Transient left bundle branch block associated with favipiravir treatment for coronavirus infection

The coronavirus disease 2019 (COVID-19) may lead to a wide spectrum of clinical manifestations ranging from asymptomatic to symptomatic by having targets on various tissues such as lung parenchyma and myocardium (Shahrbaf et al., Cardiovasc Hematol Disord Drug Targets. 21(2):88–90, 2021). As an RNA-dependent RNApolymerase inhibitor, favipiravir has been proposed as a treatment in clinical studies done during the pandemic period (Furuta et al., Antiviral Res. 100(2):446–454, 2013). Although favipiravir is generally a safe medication, it may rarely cause cardiac adverse effects (Shahrbaf et al., Cardiovasc Hematol Disord Drug Targets. 21(2):88–90, 2021). To the best of our knowledge, favipiravir has not been reported to cause left bundle branch block (LBBB).