Introduction: Antiviral drug remdesivir used in treatment of COVID-19 has been observed to have cardiovascular side effects, most commonly sinus bradycardia (1). Previously published research suggests bradycardia caused by remdesivir might be a positive effect (2). Our research aims to investigate impacts of remdesivir use in patients with atrial fibrillation (AF).

Patients and Methods: Our study included 5959 consecutively hospitalized severe and critical COVID-19 patients among which 876 received remdesivir with 876 matched controls. We compared the primary outcome, in-hospital death, in remdesivir treated AF patients compared to AF patients without treatment.

Results: 188 (10.4%) of analyzed 1752 patients had AF, with prevalence comparable between groups (10% in remdesivir group vs 11,4% in control group). Overall, while patients with atrial fibrillation experienced significantly worse mortality compared to those without (50.5% vs 29.2%, p<0.001), when treated with remdesivir, the increased mortality was significantly smaller (43.2 vs 27.7%, OR 1.98, P<0.001) compared to the AF patients in the untreated group (57 vs 30.8%, OR 2.97, p<0.001), however these benefits were not evident in those requiring high flow oxygen therapy or mechanical ventilation at beginning of treatment.

Conclusion: Atrial fibrillation is associated with increased mortality in severe and critical COVID-19, however early application of remdesivir might improve survival in this patient subgroup. Additional research is required to improve treatment.