Anotomic interaction between the aortic root and the atrial septum: a prospective echocardiographic study

We recently demonstrated that patients with platypnea-orthodeoxia syndrome and an enlarged aortic root had a smaller and hypermobile atrial septum (AS) compared with those with a normal aortic root. However, this was a partly retrospective study.

In all, 72 patients underwent transesophageal echocardiography and cardiac catheterization. The aortic root diameter, AS dimension, AS oscillation amplitude (ASo), and atrial pressure gradient were measured.

Significant correlations were found: aortic root diameter and AS dimension (r = -0.5, P < .001), aortic root diameter and ASo (r = +0.3, P = .014), AS dimension and ASo (r = -0.28, P = .02), and ASo and atrial pressure gradient (r = -0.36, P = .003). Nineteen patients presented with patent foramen ovale; those with grade 3 shunting had significantly higher mobility of the AS and larger aortic roots.

These results confirm that an increasing aortic size affects the AS by decreasing its apparent size and increasing its mobility. In case of a patent foramen ovale, increased AS mobility is associated with greater shunting.