Interatrial septal aneurysm
Interatrial septal aneurysm or atrial septal aneurysm (ASA) is defined as an abnormal protrusion of the interatrial septum. The exact length of the protrusion that defines an interatrial septal aneurysm varies in the literature, ranging from >11 mm to >15 mm beyond normal excursion in adults 4-5 and 5 mm in children.
It can be limited to the fossa ovale or involve the entire interatrial septum.
It is encountered in approximately 1% of the paediatric population.
Interatrial septal aneurysm is associated with an increased incidence of peripheral arterial embolism and increased stroke risk.
It is known to be associated with the following:
- some consider an aneurysm of more than 10 mm excursion is associated with markedly increased risk (odds ratio 8) 8
- the concurrent presence of a patent foramen ovale is thought to have a synergistic effect on stroke 8.
On imaging consider
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