Hypoxemia in coronavirus disease 2019 (COVID-19) patients is not solely due to alveolar damage but can also involve factors like vascular shunts, such as pulmonary arteriovenous malformation, contributing to persistent hypoxemia. We report a case of a 59-year-old male, with COVID-19 pneumonia, requiring high-flow respiratory support, who later was also diagnosed with a large pulmonary arteriovenous fistula, which probably worsened because of COVID-19 infection.