Transient left ventricular clot in COVID-19-related myocarditis is associated with hypereosinophilic syndrome: a case report.

Frequent clinical presentations have been reported in patients with Coronavirus disease 2019 (COVID-19). It may be associated with multi-organ and cardiovascular involvements such as myocarditis and clot formation. Hypereosinophilic syndrome (HES) is a rare disease diagnosed with idiopathic eosinophilia and organ involvement. Here, we report a patient with COVID-19 who presented with clot formation and myocarditis. One month after discharge, regarding persistent peripheral/bone marrow hypereosinophilia and clot in echocardiography, fluorescent in situ hybridization (FISH) analysis was done that showed FIP1L1-CHIC2 fusion (PDGFRɑ rearrangement) in 18% of scored cells and PDGFRβ rearrangement in 12% of scored cells, which confirmed HES diagnosis. Clot formation may be a late manifestation of COVID-19 or myocarditis due to COVID-19, or the first manifestation of HES that COVID-19 might provoke in this rare syndrome.