COVID-19-Induced Left Atrial Appendage Thrombus.

Left atrial appendage (LAA) thrombus formation is a clinically significant complication that can occur in patients with atrial fibrillation (AF), particularly in the setting of coexisting conditions that affect coagulation. Coronavirus disease 2019 (COVID-19) has been associated with a hypercoagulable state, which may contribute to thrombus formation even in patients on anticoagulation. We describe a patient with persistent AF and recent gastrointestinal and intracranial bleeding who was incidentally found to have COVID-19 infection and was diagnosed with a large LAA thrombus. This case highlights the complex interplay between infection, underlying cardiac arrhythmia, and bleeding risk, emphasizing the importance of early recognition and careful management of thromboembolic risk in high-risk patients.