How is an interatrial septal aneurysm typically visualized in transthoracic echocardiography (TTE)?

An interatrial septal aneurysm is typically visualized in transthoracic echocardiography (TTE) as a stretched or floppy septum that displaces towards one side. The imaging will reveal an abnormal motion of the septum, which often bulges into the left atrium during the cardiac cycle. This characteristic appearance is a key indicator of an aneurysm, as it differs significantly from the normal, rigid structure of the interatrial septum.

Normal septal motion maintains a more stable, midline position without significant displacement. In contrast, a stretched or floppy appearance highlights the loss of structural integrity within the septum. The visualization of this condition is crucial, as interatrial septal aneurysms can have clinical implications, including the potential for thrombus formation and increased stroke risk.

The thick and rigid appearance, normal appearance, or calcified appearance would not accurately reflect the dynamic behavior of the septum associated with an interatrial septal aneurysm, which is why these descriptions do not represent the typical findings seen in echocardiography.