An unusual cause of subaortic stenosis.

A 63-year old man with a significant left ventricular outflow obstruction due to an aberrant sub-valvular mitral tissue (not characteristic of a classical subaortic web; Fig. 1a and b), underwent resection of the mass and septal myectomy through a trans-aortic approach (Fig. 1c). Postoperative echocardiography demonstrated a reduction in the subaortic resting gradient of 70%, with no evidence of an outflow tract obstruction (Fig. 2).