Membranous subaortic stenosis complicated by aneurysm of the membranous septum and mitral valve prolapse.

The clinical, echocardiographic, and catheterization findings in a patient with discrete subaortic stenosis, aneurysm of the membranous interventricular septum, and mitral valve prolapse are presented. Echocardiography showed a subaortic membrane, abnormal aortic valve motion, accentuated systolic anterior motion of the membranous interventricular septum, and prolapsing mitral leaflets. Cardiac catheterization confirmed the diagnoses. The possible functional interrelationship of these lesions is discussed.