Posts Tagged ‘inter atrial septal bulge’

This is a relatively common abnormality of IAS. It is  often observed  as  IAS bulging  into left  or right atrium  in routine echocardiogram.If this happens without  atrial hypertension it is termed as IAS aneurysm .

This is due to valve of foramen ovale bending into the RA/LA*  cavity for various distance. By definition , the radius of curvature of  the bulge should be more than 10 mm to label it as IAS aneurysm.

*Bulging into RA more common

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General features

  • Mostly a benign entity.
  • More often observed  in  association with PFOs or ostium secundum ASD.
  • When occurs in isolation does not result in any shunting across it
  • The septal bulge can be static or  dynamic . It could swing  into LA, RA, and back to LA or vice versa.
  • Anatomically 5 types are proposed.
  • Multiple fenestration in the aneurysms have been noted.
  • Aneurysm  formation may aid in spontaneous closure of ASD.

Clinical  implications

  • IAS aneurysm tend to aggravate  stasis of LA  blood flow and predispose to minute LA clots and systemic thrombo embolism .
  • IAS aneurysm can act as an arrhythmic focus , generating focal atrial tachycardias.
  • A non ejection click  may be occasionally heard as  the IAS aneurysm  bulges and tenses within LA/RA cavity .


1 . Olivares -Reyes A, et al. Atrial Septal Aneurysm: A new classification in 205 adults. J Am Soc Echocardiogr

2. Longhini C, et al. Atrial septal aneurysm: echocardiographic study. Am J Cardiol 1985;56:653-67.

3. Gondi B, Nanda NC. Two-dimensional echocardiographic features of atrial septal aneurysm. Circulation 1981;63:452-57

4. http://www.fac.org.ar/revista/00v29n4/congreso/premio3.PDF

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