Quantitative assessment of atherosclerosis by electron beam tomography

found a higher incidence of mitral chordae attachments to the interventricular septum in patients with subaortic stenosis, they did not comment on mitral valve function. Our report differs from this previous study by including only surgical patients so that direct observations of the membrane attachments were available. In this study 11 , no patient had accessory mitral valve attachments to the interventricular septum. In addition, our report design focused on evaluating MR. To avoid confusion with physiologic MR (common in this age group), patients with trace MR were considered to have physiologic MR and placed in the group without MR. We found the indexed aortic valve to membrane distance to be signifi cantly greater in the group of patients with MR. The mechanism for the development of MR in patients with subaortic stenosis is not well understood. One explanation may be the mechanical tethering of the anterior mitral valve lea fl et toward the interventricular septum by the membrane attachments to the 2 structures. This may result in tenting of the leafl et as seen by 2-dimensional echocardiographic imaging (Figure 3). This tenting may affect leafl et motion, preventing normal leafl et coaptation. This theory is supported by the resolution of MR in most of our patients after surgical resection of the membrane. Surgical resection of all membrane attachments from the anterior mitral valve leafl et may be necessary to prevent MR. Although the incidence of aortic regurgitation is also reported to be higher with membranes that are more displaced into the left ventricle, the mechanism for the development of MR differs from that of aortic regurgitation 4 : where the high-velocity