Mitral valve echocardiographic pattern within the left atrium.

In a patient with a left atrial myxoma, the tumor adhered to the anterior leaflet of the mitral valve. This caused movement of the tumor's stalk in the left atrium in a pattern similar to that of a mitral valve in M-mode echocardiography. An accurate diagnosis was made by cross-sectional echocardiography and confirmed at surgery.