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← Section IV · Congenital Heart Disease
IV.D

Mitral Valve

6 cards

Notes

Cleft mitral valve

  • Splitting of the anterior mitral leaflet in a superior-inferior direction.
  • Associated with primum ASD / AVSD spectrum.
  • Produces MR with a jet directed toward the LV outflow.

Parachute mitral valve

  • All chordae insert into a single papillary muscle.
  • Subvalvular mitral stenosis results from restricted leaflet motion.
  • Component of Shone complex.

Supravalvular mitral ring

  • Fibrous ring above the mitral valve annulus in the LA.
  • Can obstruct LV inflow (mimics MS).
  • Component of Shone complex.

Congenital mitral stenosis

  • Multiple causes: parachute MV, supravalvular ring, thickened leaflets, hammock valve, double-orifice MV.
  • Anterior leaflet doming with concavity toward LV - similar to rheumatic MS.
  • Rare in adults; usually diagnosed in infancy/childhood.

Shone complex

  • Sequential left-sided obstructions:
    1. Supravalvular mitral ring.
    2. Parachute mitral valve (subvalvular MS).
    3. Subaortic stenosis (membrane).
    4. Coarctation of the aorta.
  • Any one obstruction may be dominant; screen for all.

Congenital mitral regurgitation

  • Causes:
    • Cleft AMVL (part of primum ASD/AVSD).
    • Endocardial cushion defects.
    • Isolated papillary muscle abnormalities.
    • Straddling MV - chordae insert on both sides of the septum in AV canal defects.

Cor triatriatum sinistrum

  • Fibromuscular membrane divides the LA.
  • Doppler gradient in BOTH systole and diastole (distinguishes from valvular MS).

Cards

  • basicIV.D-001
    What congenital defect is commonly associated with a cleft anterior mitral leaflet?
    → Primum ASD (partial AVSD). Endocardial cushion defects generally involve the mitral valve to varying degrees. Isolated cleft AMVL is rare.
  • basicIV.D-002
    Describe a parachute mitral valve.
    → All mitral chordae insert into a SINGLE papillary muscle. Results in subvalvular mitral stenosis. Component of Shone complex.
  • basicIV.D-003
    List the four obstructions of Shone complex.
    → 1) Supravalvular mitral ring. 2) Parachute mitral valve (subvalvular MS). 3) Subaortic stenosis (membrane). 4) Coarctation of the aorta.
  • basicIV.D-004
    Cor triatriatum sinistrum — key distinguishing Doppler finding vs valvular MS?
    → Cor triatriatum produces a pressure gradient across the LA membrane BOTH in systole and diastole. Valvular MS produces a diastolic gradient only.
  • basicIV.D-005
    What is a supravalvular mitral ring?
    → A congenital fibrous ring in the LA above the mitral annulus that obstructs LV inflow. Component of Shone complex; mimics mitral stenosis.
  • basicIV.D-006
    What is a 'straddling' mitral valve?
    → Mitral chordae insert on BOTH sides of the interventricular septum (rather than only the LV). Seen in complex AV canal defects and complex CHD.