Echocardiographic examination of the posterior atrioventricular groove.

Abnormalities of the posterior atrioventricular (AV) groove may be mischaracterized or overlooked in the course of routine echocardiographic imaging. Vascular abnormalities in this location include plethora of the coronary sinus and ectasia of the circumflex coronary artery. Excess accumulation of calcium (mitral annular calcification) and of fat (lipomatosis of the posterior AV groove) may also occur in this region. Masses (tumors or thrombus) arising from the floor of the left atrium or extrinsic to it (hiatal hernia, lymph nodes) may occupy the posterior AV groove. Abnormalities of the left ventricle, including aneurysms and pseudoaneurysms may present as masses in the posterior AV groove. This article discusses the echocardiographic features, differential diagnosis, and clinical significance of these abnormalities.