Echocardiographic diagnosis of left ventricular outflow tract obstruction caused by an acquired subaortic membrane after mitral valve replacement.

Although an acquired subaortic membrane has been reported as a cause of left ventricular outflow tract (LVOT) obstruction in various clinical settings, it previously has not been reported after mitral valve surgery. We describe 3 cases of acquired LVOT obstruction that resulted from development of a subaortic membrane after mitral valve replacement. This report emphasizes the role of an acquired subaortic membrane in LVOT obstruction after mitral valve replacement, the use of echocardiography in diagnosing this condition, and the importance of early intervention.