Annular subvalvular left ventricular aneurysm mimicking a pericardial effusion on echocardiogram.

Annular subvalvular left ventricular aneurysms are a rare form of herniation of the left ventricle, reported usually in negroes. These aneurysms are situated beneath the mitral or aortic valves and extend along the line of the valvular annulus. The aetiology remains speculative but is not associated with coronary artery disease. Our patient was Caucasian and a review of the literature reveals only four other documented cases in Caucasians. Our case corresponds completely in pathological detail with previous cases. This condition has never been reported in Australia. The echocardiographic features have not been described before. These are the presence of a large echo free space behind the left ventricle, without an interior free space. These features are not specific but this type of aneurysm should be considered in the differential diagnosis of a loculated posterior pericardial effusion, along with a large left atrium and a hernia through a patent foramen of Morgagni.