Subaortic Stenosis – Membranous

 

appear to arise from the membranous septum, although they may arise from a thickened muscular ridge slightly further down into the ventricle

Attachments to the anterior leaflet of the mitral valve are frequently seen.

  • rare in newborns and infants.
  • progresses over time s
    • ?acquired
      • ? due to thickening and scarring from  turbulence caused by an underlying  LVOT abnormal architecture.
Subvalvar Aortic Stenosis
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3D transesophageal echocardiography demonstrating circular subaortic membranous stenosis, with a planimetric orifice area of 1 cm2.
2D transesophageal echocardiography. Membranous subaortic stenosis in the left ventricular outflow tract (yellow arrow) extending to the anterior mitral valve leaflet is seen on the left side of the figure; a turbulent blood flow pattern through the membranous subaortic stenosis is shown on the right side of the figure.

 

Perioperative image confirming the presence of a circular fibrous membrane in the left ventricular outflow tract.
Membranous Subaortic Stenosis
LV angiogram in RAO projection shows a thin subaortic membrane (arrows)
Ashley Davidoff
Membranous Subaortic Stenosis
LV angiogram in LAO projection shows a thin subaortic membrane (arrows)
Ashley Davidoff
Membranous Subaortic Stenosis
White blood imaging in the coronal plane shows a subaortic membrane in the LV outflow tract
Ashley Davidoff
86548
Membranous Subaortic Stenosis
White blood imaging in the sagittal plane shows a subaortic membrane in the LV outflow tract
Ashley Davidoff
86551
Membranous Subaortic Stenosis
White blood imaging in the axial plane shows a subaortic membrane in the LV outflow tract
Ashley Davidoff
86553