Impending paradoxical cerebral embolism in a patient with atrial septal aneurysm.

There is increasing emphasis on the role of interatrial septal abnormalities, including patent foramen ovale and atrial septal aneurysm, in the genesis of stroke. However, a transseptal thrombus located in both atria is rarely visualized by echocardiography or other cardiac imaging techniques. It is also difficult to prove the mechanism of stroke in most clinical settings. In the present case of impending paradoxical cerebral embolism, the thrombus penetrating the atrial septal wall was visualized by transesophageal echocardiography.