A 77-year-old woman presented with a feverish hemodynamic collapse, acute respiratory distress, and dorsal pain, initially treated as a septic shock. Transthoracic echocardiogram revealed an impressive compression of the left atrial cavity, by an extrinsic mass preventing the left ventricle from refilling. Thoracic computed tomography revealed a large hemomediastinum emerging from an aneurysm of the descending thoracic aorta compressing the left atrium. The patient died in refractory cardiogenic collapse. <Learning objective: In the management of cardiovascular collapse, the understanding of the mechanism or the cause is essential. For this purpose, echocardiogram is a fast and indispensable tool, sometimes allowing discovering surprising etiology.>.
Keywords: Cardiogenic shock; Left atrial compression; Thoracic aortic aneurysm.