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What is the simplest way to differentiate pseudo normal mitral infow doppler from normal ?

Posted Jan 08 2010 10:24am

Diastolic dysfunction  as concept  has  come a  long way after  initial hiccups . Now,  it is a well established  left ventricular pathology  , and has   a  sound physiological and molecular basis. Even though there are variety of methods available to quantify  LV diastolic function,  echocardiogram is the simple method to identify and grade diastolic dysfunction.

There are 4 grades of diastolic dysfunction

1.Impaired relaxation  (without elevated filling pressure)

Some  describe another grade  1 a  with elevated filling pressure

2.Pseudonormal mitral inflow

3.Restrictive -Reversible

4.Restrictive -irreversible

What is pseudo normal pattern ?

The grade 1 is the  most common type  diagnosed  . It is diagnosed when the  A  velocity is more  than E velocity . This  simply implies ,  ventricular filling needs greater assistance from atrial contraction than in resting conditions. It is so common , especially in elderly ,  many thought it should not be considered a pathology . In youngsters it is definitely pathological especially if it is persistent.

The issue that  really concerns  us  is  this  : When the diastolic dysfunction  progress  from grade 1  to grade 2  ,  the mitral the inflow  doppler pattern ,  instead of showing any  new changes simply nullifies the changes that occurred in grade 1 and  records a normal E : A velocity .

So , a person with grade 2 diastolic dysfunction will have a near normal pattern .Of course  deceleration time, and IVRT is shorter than in grade 1 but it is not very useful in differentiating it from normal .

Pseduonormal is  actually  equivalent to moderate diastolic dysfunction , but the abnormality is masked  as near normal  filling is restored with atrial assistance . So,  technically it a  assisted LV filling . A  superficial  look at the doppler pattern may exactly mimic normal . But there will be a  2 D echo  abnormality  that makes the patient  pathological . Our eyes need to look  beyond  doppler  ( in coherence with  2 D ) to differentiating  normal or pseudo normal.

It is learnt  ,  2D abnormality of LV or LA occurs in nearly 90 % of grade 2 diastolic dysfunction .(There can be a pure functional grade 2 diastolic dysfunction  without structural changes in LA/LVH in minority -This is poorly understood form of silent sub clinical CAD manifesting only as diastolic dysfunction  )

Traditionally  there are few methods taught  in echocardiaographic schools  all over the world to differentiate normal from pseudonormal

1.Pulmonary vein  doppler

2.Response to valsalva maneuver

3.Tissue doppler etc

One simple echo feature  that is   often forgotten , that can be really useful in differentiation of  normal from pseudo normal is    left atrial dimension

While patient with pseudonormal who  have  progressed   into  stage 2  will show a  definite left atrial abnormality .

When does a left atrium begins to enlarge in diastolic dysfunction?

  • It depends  on LA thickness  and  LA afterload (LVEDP is the afterload for LA)
  • It is generally believed  LAE  will be there in almost all cases of grade 3  diastolic dysfunction.
  • It is present in  majority of patients  with grade 2 as well . But the degree  of LAE may be less  ( 4-4.5cm)

It is yet unclear ,  the onset of LA enlargement in diastolic dysfunction .This is potentially a research topic for the fellows !

It is not uncommon  to find   LA enlarge  like a balloon even in stage 2  of diastolic dysfunction. So , in patients who are suspected to have  pseduonormal  doppler profile , look for the presence of LAE  , (however mild it may be !)  , there is no business for LA to enlarge in normal persons.

Ofcourse , if  you are a echo expert one can measure A reversal in PV doppler, tissue doppler echo etc .But remember a simple 2D echo feature like a LA dimension / LVH   may score over the sophisticated (Also read complex  . . .) parameters  in the grading of diastolic dysfunction

Final message

While  we  immerse  ourself  in   sophisticated doppler methods  to differentiate normal from psedunormal pattern, the fact that  , normal persons will  have normal hearts  is often forgotten , and    presence of left  atrial enlargement (Which is all too common in pseudonormal !)  straightaway   settles the issue . Detailed diastolic function studies are warrented only if the LA size is normal .

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