Rationale:Echocardiography is essential in establishing the diagnosis in patients with cardiac masses. The differentiation between myxomas and thrombi is sometimes difficult, but is critical in making the right therapeutical decision.

Objective: A 70–year–old female presented to the Emergency Department with palpitations, dyspnea and anterior epistaxis. She had a 3 years history of atrial fibrillation and chronic heart failure NYHA class III.

Method and Result: Two-dimensional transthoracic echocardiography showed the thickening of the mitral valves with moderate mitral insufficiency and a mobile round mass in the left atrium, heterogeneous, inhomogeneous, 18 mm in size, attached with a narrow stalk to the interatrial septum, reaching mitral annular plane; tricuspid insufficiency with a maximum 30 mmHg gradient, intact interatrial septum, akinesia of two thirds of basal inferior wall, 42% ejection fraction.

Discussion: The two–dimensional transesophageal echocardiography confirmed the intraatrial mass. Epistaxis was considered to be due to heart failure and the increased venous pressure. The patient was referred to the cardiovascular surgery clinic, but refused surgery. Anticoagulation with fraxiparine 0,6 ml/day was started and continued for 3 weeks, after cessation of epistaxis by nasal tamponament. Then echocardiography was repeated, with no remnant mass in the left atrium. The conclusion was that the mass must have been a thrombus that has melted away. In this particular case, the left intraatrial thrombus may have been due to the presence of atrial fibrillation.