Posts Tagged ‘mitral regurgitation’

There are many  organic causes of mitral regurgitation. ( Ischemic , degenerative , valvular , cardiomyopathy etc.) It is not  rare for  pure  electrical events to result in valvular regurgitation.   A 70year old  man  with SHT   presented  with palpitation  and exertional dyspnea  .He was  later referred  for  Echocardiography.  Echo revealed LVH with intermittent MR and moderate LV dysfunction.

His ECG looked like

Ventricular ectopic recorded in bi-geminal rhythm

His  echocardiogram showed


His echo showed randomly timed mitral regurgitation was detected .See the Doppler MR jets below.

We know ventricles are integral  part of mitral valve apparatus  .Hence  it  wouldn’t  be a surprise to note  abnormally timed ventricular contraction  can  have a major impact  on mitral valve function.

When ventricles  prematurely begin  to contract  ( As  during  VPDs) it  interferes with  opening of mitral valve. In other words every VPD  technically imparts a  sort of  diastolic dysfunction !

VPDs occur in which part of cardiac cycle ?

VPDs  occur  either in early   or mid  diastole . Thank fully VPDs can not occur in systole . (Refractory period )

What would be the status of mitral valve at times of  VPDs?

Though it depends upon the timing of VPD ,  generally it interrupts the rapid inflow period of diastole .

In fact ,  it converts the cardiac  cycle from diastole to a partial systole or  a combination( fusion ) of diastole   and systole ! *

More MR jets are visualised than LV filling waves . Note the some of the E waves are sandwiched between two MR jets. ECG gating should have made this image more interesting .Any way , we have good MR jets to time systole nicely

* Is that a funny  imagination  ?

During   diastole ,  if  LV suddenly  begins  to contract   instead of  receiving the blood  ,  what will happen ?

VPDs are such a common arrhythmia , we  rarely  wondered  ,  it can have a dramatic  consequence  in a any  given cardiac cycle .While   the cardiologists think too  technically  their  patients observe with  shrewd  sense and tell us clearly  what  they feel  is  actually a   missed beat !

(Yeh  . . .  how simple  they describe the complex  hemo-dynamics  of  missing  diastole !)  .They also tell  us ,  next systole is felt as big thump as palpitation . (Post VPD potentiation )

Just imagine ,  if a patient  has  multiple VPDs  with  different  coupling intervals   that fall in different location of diastole  also  interspersed with sinus beats ,   how chaotic  would be the  the  mitral   filling .

This is what  is recorded in the above patient with multiple random MR jets .

Why all VPDs do  not cause MR ?

The timing is critical .We know all VPDs do  not generate a powerful contraction to cause MR. Atrial fibrillation, Prolonged PR intervals , heart blocks , critically raised LVEDP all can influence the trans mitral gradient . In fact these situation can result in  an  entity called diastolic MR that would be discussed later.

Can  VPD induced MR be  referred to  as diastolic MR ?

When VPDs  occur  in  diastole  , it  interrupts the diastole  and a new systole begins. In any  particular point of time there will be  leak into the LA  if the mitral valve is open .This is technically a new systole but in true sense it is the diastole of  the  previous beat . I wonder , whether   VPD induced MR  may be referred  to as one  form of  diastolic MR.  Of course ,  this MR can spill over to true  systole as well .

This also  makes  sense (Non !) as many of the VPDs do not open the  aortic valve ,   hence technically we can’t call the phase reset  by  all  VPDS   as a true systole !

What is the effect of VPDs  on pulmonary venous flow ?

Left atrial  cannon waves can occur that can elevate PCWP .This is the prime reason for resting or  exertional  dyspnea in these patients. Some may get a paradoxical relief  during exertion   as  exercise  suppress VPDs which are frequent at rest.

If VPDs can seriously interfere with mitral valve function , why  they are  often  considered benign  ?

VPDs are well tolerated* as long as  the  LV function is intact.  If VPDs are associated with  LV dysfunction  it  can initiate a vicious cycle of   hemodynamic deterioration .  Multiple VPDs  if left untreated can lead to progressive LV dilatation  in a  significant population .  Hence patients with  recurrent VPDS need some sort of  follow up. It  makes good medical sense to suppress VPDs in the long run. (Of course the  available anti VPD  drugs  are not very safe  !  The search for non toxic ,  ideal drug should go on !)

*”Well tolerated VPDs”   in no way  means  normal physiology.  Read a related article in my site.  “3 minutes crash course on VPDs”

Final message

VPDs  though considered  largely benign , can lead to dramatic  alterations in the  functions  of mitral valve , especially in diseased hearts.

We  must  realise  when ventricular  ectopic beats occur frequently  , it  interfere with the  both opening and closing of mitral valve.

It is really surprising  ,  the literature is  devoid of  major studies  about the  impact of  VPDs on  mitral valve  physiology . . . rather pathology !

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Mechanism of chest pain in mitral valve prolapse  include

  1. Mitral valve  has pain fibers , the myxomatous degeneration  of the valve tissue generates pain .* (Not much evidence )
  2. Mitral valve stress, strain ,  stretch and bending.
  3. Mechanical stretch  of papillary muscle or LV free wall (dimple ?  ) as the mitral valve prolapse into LA.
  4. It is a central pain perception disorder .Panicky and anxiety reactions included
  5. It is not chest pain  at all it is simply a feeling of palpitation .
  6. Associated ischemic  heart disease

The commonest mechanisms  are   response  4 and 5 .

The evidence  lies in the fact ,  many of  these people  begin to complain of chest pain only after being aware this problem. MVPS is  often a  fancy entity created by cardiologists  which  unfortunately has  labeled  many of the normal  general population as cardiac patients. Barlow who described this entity  decades ago  would have never imagined  it  would be  so popular and subjected to mis-use . We have proposed a solution for this . The diagnosis of MVPS shall not be mentioned unless it is obvious  and fulfill a strict criteria . The commonest error we make is  an elongated , redundant , hyper mobile mitral leaflet   at   as  MVPS.

It is expected  ,  true MVPS must have all of the following  three criteria

  • Thickened leaflets
  • Clear prolapse of  at least one leaflet in long axis view beyond the plane  of  mitral annulus
  • At least some degree of mitral  regurgitation must be present

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Mitral regurgitation is  one of  the most common lesion of rheumatic heart disease .Mechanism of MR in acute rheumatic fever is different from chronic rheumatic heart disease.

Acute Rheumatic fever

The following mechanisms contribute to MR of acute rheumatic fever

  1. Edema of leaflets (Carey Coombs murmur )
  2. Valvulitis
  3. Small verrucous  vegetations (See Image )
  4. Acute LV dilatation in fulminant cardiac failure.

* Note  : Acute rheumatic fever in its first episode can never  cause stenosis  however fulminant the fever may be  .There is no acute mitral stenosis .But ,  during recurrence and reactivation some amount of stenotic process may occur.  Still ,  recurrence and reactivation are more often related to significant MR rather than MS. ( Isolated mitral stenotic lesions  rarely  give h/o recurrent rheumatic fever )

Chronic rheumatic  heart disease

As the mitral valve gets progressively damaged  any combination of MS or MR occur .The following mechanism are involved in  the genesis of MR. (Pathology of Mitral stenosis is not discussed here)

  1. Chordal shortening, tethering , pulling , prevent proper co-optation
  2. Chordal lengthening
  3. Chordal disruption (Minor > Major )
  4. Prolapse of either AML or PML (Not both ,unlike myxamatous MVPS)
  5. Infective endocardits  of  leaflet
  6. Perforations of  leaflet
  7. Annular  dilatation
  8. Fibrosis of posteromedial/Antero-lateral   pap muscle(Rare )
  9. Left atrial pathology

* The direction and the  width of MR jet is  related to the mechanism of MR.

If there is chordal shortening due to fibrosis  of mitral valve  co -optation plane is altered . The degree of chordal shortening , pap muscle fibrosis (rare)  symmetry of chordal involvement determine the MR.

Rheumatic mitral valve prolapse

  • This could be  more common than we realise.
  • It can be true or pseudo.
  • True prolapse occur due to chordal weakening or lengthening .
  • In chordal disruption the leaflet tips usually become flail

Since rheumatic process fixes the PML first , the AML   appear to overshoot the plane of PML and   appear as prolapse.(Pseudo )

The sail like AML commonly  directs the jet posteriorly and laterally .(Murmur conducted to axilla and back )

It is rare for PML to prolapse in RHD , if  it does occur ,  it directs the jet anteriorly (murmur conducted to aortic area mimic AS !)

It is rare to see a  perfect  central jet in RHD  . presence of  Central jet is a good sign to consider mitral valve repair.

Myocardial involvement in RHD.

Even though rheumatic fever is a classical  example for  pan-carditis , it is surprising   to note (Of course fortunately !)   how  myocardium escapes in the  chronic process of RHD.

Is it really true  ,  myocardium do not get involved in chronic RHD ?

Clinical cardiologists rarely discuss this issue. Pathogists indeed have documented significant lesions within myocardium  . Involvement of left atrial myocardium and  rarely  ventricular myocardium in the sub mitral  zone  can influence the  degree of  MR

* Even in acute rheumatic fever with fulminant carditis , myocardial involvement is  disputed by many  ! . My belief is ,  there will   definitely a subset  in   both acute and  chronic  forms of   RHD   , in which myocardium  gets  involved . In our institute LV dysfunction associated with RHD occur in  up to  5 % of  RHD population .

Importance of knowing the mechanism of MR

Two aspects  appear important

1. Is there a potentially  reversible component in pathology so that we can  wait  before intervention  ?

I have seen children referred for mitral valve replacement due to severe MR  . In due course   MR regress by the time they reach the tertiary center (waiting period included ) At least one child i remember,  the MV surgery was canceled  due to spontaneous regression MR.

It was later found the MR was  more of valve inflammation than degeneration .

* Always think about the possibility of reversible rheumatic MR  in every severe isolated  MR in children (Do not apply this rule in adults or in combined MS or MR  )  Do a ESR, ASO and start an  intensive anti inflammatory therapy  , aspirin with strict penicillin prophylaxis .With this  one can definitely postpone the surgery  in few cases  and  may avoid it altogether !

2. Surgical implication

If we could delineate  the  exact pathology of MR   it will facilitate  the   repair . Annular  reduction and  neo  chordae  etc . Of course ,the surgery could be  very  difficult in scarred mitral valves ,  Dr Sampath kumar *of AIIMS  New delhi , India  would  feel other wise !

*A pioneer in mitral valve repair in chronic  RHD (See reference 2 )

Questions  that need  answers

How is balloon/Surgery  related injury different from rheumatic process ?

Why is  rheumatic  mitral vale  prone for bacterial infection ?

What is the relationship  between  extent of  aortic valve involvement and  degree of mitral valve involvement in RHD ?



2. http://icvts.ctsnetjournals.org/cgi/reprint/5/4/356


There two popular books exclusively  for cardiac pathology


2. Renu Virmani

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A young women  with Rheumatic heart disease .


LA aneurysm

Giant left atrium in rheumatic MS . http://www.drsvenkatesan.com

Mitral regurgitation is significant .www.drsvenkatesan.com


When do you call  a left atrium as   giant  ?  When it is referred to as  Aneurysmal dilatation ?

It is all semantics. Whenever LA becomes more than 6 cm ,  at least in two diameters  many prefer to call it giant .

In India , 6 cm LA is such a common finding , we have kept a  cut off at an  arbitrary 9 cm .

What factors determine a LA to dilate like a balloon ?

The exact mechanism is not known.It could be  the  intrinsic weakness of LA wall ,  as very few with RHD develop this. Many LAs resists dilatation even in the midst of extreme LA pressure. But , it is a well-known fact , mitral regurgitation provokes greater LA dilatation than MS alone .This implies volumetrics  play a major role than  pressure dynamics  in determining LA size. Acuteness of hemodynamic insult is  inversely proportional to LA size.

By the way, what is the purpose of  recognizing  the LA as Aneurysmal ?

  • In plain X -ray chest , LA may  form the right heart border  over shooting the RA.
  • When LA becomes huge  , there is a  chance for mechanical complications  like dysphagia, phrenic nerve , bronchial compression etc .
  • Giant LA invariably increases the chance of LA clot.

Electro-physiological Issues

  • Atrial fibrillation , a usual accompaniment of giant LA ,  is often refractory . There is no  purpose  to convert to sinus rhythm . In fact ,  one should not attempt this. There was a time when surgical incisions  ,corridors , mazes were quiet popular.Now it is believed all these are adding further injury to the ill-fated LA .Electro-physiologists should be restrained . Pulmonary vein ablation should never be attempted in such cases as the focus of AF is elsewhere .

Implication in cath lab

During PTMC LA size can be an issue  as the plane of IAS is distorted and make things difficult for septal puncture . Further the balloon , guidewire  may often slip  back into RA .

Implication for the surgeon.

For the surgeon the implication could be more. As a cardiologist I can’t comment about that .One thing we have observed is when LA becomes huge , the size of mitral annulus is too fictitious and funnily enough we have recorded up to 6 cm of mitral annulus . No valve is available for this size . We learnt from the surgeons ,   large LA  rarely pose a  problem as they suture the much  smaller valve in a larger annulus .(Which  makes the task  that easier )

Does the LA size regress after surgery ?

In many  it does regress  , in as many it doesn’t. We have seen giant LAs continuing to trouble the patient even after a successful mitral valve replacement.

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Echocardiography is about 50 years old tool.It has evolved from simple M mode to sophisticated tissue Doppler and 4D imaging. Color Doppler imaging was a great revolution ( One  can  consider it  as big as invention of ultrasound itself  !)

Even though , we could code the pulse Doppler samples into color coded pixels (Called auto correlation computed by Fourier algorithm) the full potential of color Doppler is yet to be explored. Accurate assessment of regurgitation  lesion severity continue to trouble  us  .

The PISA concept fizzled out due it’s complexity and   inaccuracy.It  exhausted  thousands of  cardiology man  hours  and  precious  academic time ! (Not really waste . . .it stimulated our intellect !)

I wonder we have a method to predict  early  “The would be failed concepts”  in medicine !

Vena contracta* Who named it     http://en.wikipedia.org/wiki/Vena_contracta

Suddenly common sense struck us . . .  simplicity replaced complexity . The concept of vena contracta came in to vogue.

It is a  simple estimate of the  narrowest part of a regurgitant  jet.It  is good enough to assess the severity of regurgitation .The diameter is measured  in the   zoomed up view of  the  leaky valve  aided by color flow. If it is > 6mm it is severe regurgitation .(Both AR/MR)

Please note ,it is  one of the measurement  we  take in the  dimensional regurgitant  shell of (blood dome )  in the PISA method . The harrowing exercise of calculating ERO  with all those radius and velocity etc  may be fresh in many  minds !

Can’t we extend the simplicity of  the concept of vena contracta further ?

As usual ,  we assume  many things in medicine .

Here the concept of Vena contracta(VC)  requires

  • The orifice is near circular. (Very unlikely , considering the complex shape of mitral valve especially in diseased state)
  • The vena contracta applies only to single jet MR
  • Central jet (Eccenticity increase the chances altering the shape of ERO )

but, the major advantage is VC is not much  influenced by loading conditions .And the parameter used as such without amplifying the error.

Why vena contracta  is not used to  assess mitral stenosis  severity ?

I wonder why it shoudn’t ?  The same principles apply, the flow through  narrowest point of mitral  valve  will reflect the degree  of narrowing. In fact ,the inter-leaflet distance  could be   same as  vena contracta  in mitral stenosis.

If we assume !   the orifice as a circle,  then  50 %  the vena contracta is   the radius  the orifice  and ERO  can be easily arrived .

Logically yes. We need to validate the data ,comparing with a gold standard .When there is no gold standard , and what  we are testing is  better than gold standard what shall we do ?

Final message

Complex  measurements  lead to  complex errors (Lesson learnt from PISA) , with simple parameters  errors do not get amplified.

Do not ditch any investigation just because it is simple  . . .

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Let ventricle is an elliptical or ovoid chamber .The pattern of LV enlargement can vary considerably in different pathologies. We know a dilated , globular heart is the typical feature of terminal congestive heart failure. But in the early stages of cadiac enlargement there are some distinct differences in the contour. (Aortic stenotic lesions retain the ellipitical shape till late in the course )

LV enlargement due to mitral regurgitation is somewhat different from aortic regurgitation. A globular configuration occurs more often in severe MR than AR. This is due to the fact, the long axis and short axis ratio of LV  is maintained till late in the course  of aortic valve disease . Cardiac long axis enlargement is more pronounced in aortic valve disease than in MR. The AR jet reaches LV  at a higher pressure gradient (Diastolic pressure of aorta) than mitral inflow velocity . (Often mimic physiological flow with an S3)

For a given degree of regurgitant volume AR will cause more cardiac enlargement than MR. In the same note , one should realise  the LA becomes huge in MR which receives high pressure regurgitant jet . Further ,mitral valve disease is more likely to result in early PAH and that results in right sided chamber enlargement giving the cardiac contour a more globular configuration

Is the cardiac contour different in rheumatic and degenerative(Myxamatous) mitral regurgitation ?

Yes , rheumatic MR results in less enlargement of the base of the heart as the fibrotic process restricts and restrains LV and prevents uncontrolled LV dilatation . In fact , giant LV are often  reported in mitral regurgitation due to mitral valve prolapse than rheumatic MR.

Why the configuration of LV important in the management of cadiac failure ?

The globular configuration of LV implies , the papillary muscles are attached in a disadvantaged angle and keep the free wall stress high. Specialized procedures are required to restore the LV shape especially in secondary to mitral annular dilatation. Isolated aortic valve disease rarely require LV remodeling surgeries , even if AVR is done late stages.

What is the maximum dimension of LV reported in cardiac failure ?

The upper limit of normal for LV diastolic dimension is 5.6cms. In MR it often reaches 6-7 cms . The maximum of 10cm has been reported with AR. An LV beyond this level looses it’s elasticity and likely to be incompatible with survival unless LV reduction surgeries like Batista are performed.

Is secondary valvular cardiomyopathy an accepted entity ?

 The  term cardiomyopathy when originally defined decades ago ,  required exclusion of all known cases of cardiac enlargement. But now we have a more liberal working concept , if the LV enlarges disproportionate to the loading conditions of the valvular lesions  , secondary cardiomyopathy is said to be present. If cadiomyopathy sets in,  the cardiac shape invariably takes in a globular configuration irrespective of the valvular lesions. So, the simple parameter of shape of LV in X ray chest can give us a clue regarding the outcome in valvular heart disease.

Further reading

Also read sphericity index by echocardiography A spherical LV can be easily quantified by echocardiography

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