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Posts Tagged ‘eccentric jet’

                                    Competence of mitral valve is vital  for proper hemodynamics of  heart .A trivial mitral regurgitation ,is observed in nearly 10-20% of normal population detected by doppler echocardiograpgy .This is other wise clinically insignificant. In fact , it is expected  , the sonographers do not report this,  as it might increase the patient anxiety.

Can a mildly incompetent mitral valve be a hemodynamic advantage ?

Left ventricle , physiologically can have only one exit, namely LVOT and aortic valve.If there is normal  impedance , at this level (LV after load )  it  is refered to as  physiological .In disease states , as in cardiac failure there is raised after load or LV wall stress.this makes the LV struggle to pump blood into aorta.The more the dilatation the more the wall stress (Laplace law). more the wall stress more the after load.

 The  main principle of management of cardiac failure  for decades  has been promoting  LV inotropism .Now we have realised this is fundamentally a wrong concept, (Except in acute heart failure). Hence the main option available now is to reduce the after load , ACEI do that most effectively and proven to improve survival.

What is the effect of  trivial or mild MR on LV after load  ?

It is a hemodynamic fact for MR  to increase LV contractility  and Dp/Dt  due to a relative reduction of after load.

In patients with cardiac failure , even a mild improvement in LV contractility can give a  symptomatic improvement .

 

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Can mitral valve act as controlled safety valve allowing only a trivial or mild MR ?

This may be difficult . But it happens naturally in many of our patents in cardiac failure .

Probably , these are same  patients who come under the 20% incidence of physiological  doppler  MR .Other group could  form the  functional MR*

We have found, patients with  DCM  with mild mitral regurgitation tolerate excercise better than patients who have very competent and rigid mitral valve.It is presumed a mitral valve which gives in a little bit , decompresses the LV with a symptomatic benefit.But if the MR , is occurs in an eccentric path or it results in significant volume burden the potential advantage becomes a liability.

Related issues

*Functional mitral regurgitation. Functional MR is said to occur , when patients with cardiac failure, and resultant dilatation of mitral annular ring, and lack of opposition of leaflets

While milder forms of MR are well tolerarted  , when it occurs  acutely ( even if it is mild) ,  it can be dangerous and result in sudden pulmonary edema  .This usually happens in acute MI or infective endocarditis etc.

 Final message

  • Minimal or mild  mitral regurgitation without any significant volume overloding  in some of the patients with dilated cardiomyopathy  could bring  a hemodynamic advantage .
  • So one may not unduly worry about , a mild MR (central jet) in patients with DCM.It could be after all a safety exit for overstrained LV

We will report the results of the ongoing study about the impact of presence /absence    of  mild MR on the 6 minute walk test in patients with dilated cardiomyopathy.

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