Bifid left atrial appendage with thrombus: source of thromboembolism.

Three patients with embolic events were found on transesophageal echocardiography (TEE) to have bifid left atrial appendage (LAA). In these patients, large mobile thrombi were found only in the posterior limb of the appendage. The best views to demonstrate the posterior limb were between 85 and 155 degrees from the transverse plane with the use of a multiplane TEE probe. To avoid overlooking this pathologic condition, we recommend that complete evaluation of the LAA should include rotation of the TEE transducer up to 155 degrees from the transverse plane.