inter atrial septum

whule performing echocardiography for newborns i have come across interatrial septum whicc looks like a thin membrane and is mobile with each atrial contraction, there is no drop out or flow across the septum. something like an extremely floppy septum. can we call it floppy interatrial septum? what is the protocol of follow up of these newborns? this finding involves the whole length of the septum and not merely a part of it.

[Jeffrey R Boris, M.D.]

Dear Sajidisa,
It is difficult to say exactly what you are seeing here.  The most likely thing that you are seeing is a prominent septum primum.  As long as there is no obstruction to vena caval or tricuspid valve inflow and no obstruction to flow across the foramen ovale in utero, and as long as there are no sustained tachyarrhythmias (floppy tissue in the atrium can sometimes initiate supraventricular tachycardia), this typically does not require specific follow-up.  The foramen ovale should spontaneously resolve, although 25% of all adults have a probe patent foramen ovale.  Therefore, we typically do not follow this unless there is evidence of a true atrial septal defect.

The other potential structure that you may be seeing is a prominent Eustachian valve or a Chiari network.  Again, unless these are causing obstruction to the structures mentioned above, we do not follow these.