A young man underwent Focused Assessment with Sonography in Trauma (FAST) scan for blunt abdominal trauma. An incidental finding on the pericardial view was the presence of a tumor in the right ventricle. Detailed cardiac imaging and subsequent excision revealed the presence of a myxoma. The patient had no obvious cardiac symptoms, but the awareness and experience of the examiner during the FAST examination detected this rare heart tumor at a latent stage, preventing serious, irreversible complications. This case demonstrates the potential importance of looking above the diaphragm during routine abdominal sonography, especially in patients who are critically ill.