With color Doppler mapping: in the middle third of the interatrial septum (IAS), an area of staining is visualized with a direction from the left atrium to the right atrium up to 2 mm (patent foramen ovale). There is an arcuate protrusion of the IAS towards the right atrium (aneurysm of the IAS), which periodically changes the direction of the protrusion towards the left atrium.
