Commissural mitral regurgitation detected by abnormal blood flow pattern in the left atrial appendage.

An 86-year-old man with severe symptomatic aortic stenosis underwent an aortic valve replacement. A transesophageal echocardiogram (TEE) was performed during the surgery and demonstrated mild mitral regurgitation (MR). The patient's symptoms persisted despite surgery, and subsequent TEE demonstrated prolapse of the posteromedial commissural leaflet, with evidence of a severe, very eccentric MR jet which was directed laterally and superiorly. The jet was almost missed in most imaging planes and could finally be exposed by withdrawing the probe to the level of the aortic valve and left atrial appendage.