label: Foramen ovale aneurysm
label_lc: foramen ovale aneurysm
description: "Foramen ovale aneurysm (FOA) or atrial septal aneurysm is abnormal redundancy of the atrial septum primum, with bulging of the septum by at least half the width of the atrial chamber, or by at least 10 mm beyond the level of the atrial septum. The abnormal protrusion of the interatrial septum results in decreased left atrial volume. On color Doppler there is reduced left ventricular inflow."