9. MS

Question 1

Normal MV orifice area

Answer 1

4-6 cm^2

Question 2

Grading MS

Answer 2

-Normal-
PHT: 60ms

-Mild-
Mean gradient: 6
PHT: 100ms
MVA: 1.6-2

-Moderate-
Mean gradient: 6-10
PHT: 300ms
MVA: 1-1.5

-Severe-
Mean gradient: >10
PHT: 300ms
MVA: <1

Question 3

Causes of MS

Answer 3

• ** rheumatic heart disease
• LA myxoma
• mitral calcifications
• thrombus
• congenital
• cor triatriatum

Question 4

Cor triatriatum

Answer 4

Congenital defect where atrium subdivided by thin membrane, creating three atrial chambers

Question 5

Rheumatic MS, characteristics

Answer 5

• fusion of commissures
• diffuse thickening of leaflets, esp tips
• calcification within the leaflet itself
• subvalvular thickening
• “doming” of anterior leaflet in diastole, or
  “hockey stick”
  
  • result of fusion of commissures with only
    movement of central leaflet

Question 6

MS, pressure gradient

Answer 6

• CW doppler used to determine mean pressure gradient across valve by Bernoulli equation
• High flow states (such as volume overload from mod-severe MR) will result in falsely elevated pressure gradient and overestimate restriction

Question 7

Ways to determine Mitral Valve Area

Answer 7

1. PHT: MVA= 220/PHT
   * Severe AI and poor LV compliance can
   causes falsely low PHT and overestimate
   orifice area
2. Decel time: MVA= 759/DT
3. Continuity equation
   
   • error introduced with significant regurg
4. PISA