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When does planimetery errs in estimating mitral valve orifice ?

Posted Oct 06 2010 10:26am

Planimetery is the age old method to measure the mitral valve  area( MVA) by echocardiography.


  • Simple modality
  • 2D echo  is enough
  • Doppler errors avoided
  • In the presence of MR, planimetery orifice has an edge over other methods


  • Optimal gain setting becomes  important .There is  significant inter and intra observer variability.
  • Shape of the orifice is not constant  ( MVO is funnel like) . Narrowest diameter is usually measured.
  • Planimetery is  a purely an anatomical orifice,while blood flows through both primary and secondary mitral orifices .Sub valvular fusion makes secondary MVO the  narrowest point  . Measuring it becomes difficult as it has no defintion of border.
  • Gross errors possible in calcified valve.
  • In post commissurtomy  the  lateral extent of split is often  not tractable

How to improve the accuracy of planimetery ?

Color Doppler aided  2D  planimetery . This can improve some of the limitations , as  it provides a hemodynamic MVO(Some what physiological ) Of course  , pressure halftime derived MVO is purely a physiological orifice .

Other options to measure MVO

  1. Pressure half time
  2. Continuity equation
  3. PISA method

Advantages and disadvantages  of Pressure half time derived MVO will be posted soon.

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