Submitral aneurysm with left atrial communication.

Annular sub-mitral aneurysms are rare lesions of varied etiology. A sub-mitral membranous curtain may be a potential area of weakness through which these lesions expand. Initially described in young males of African origin and reported from varying geographical areas, these lesions arise from the atrioventricular groove in close relation to the mural leaflet. They may cause pressure effects, lead to mitral incompetence and left ventricular dysfunction. Key issues during repair are proximity to the circumflex coronary artery, atrioventricular junction and progressive involvement of the mitral valve. This case report of a calcified bi-lobed sub-mitral aneurysm with communication to the left atrium discusses the anatomical basis of the lesion, the role of computed tomogram angiography in pre-operative evaluation and surgical management.