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Posts Tagged ‘diastolic dysfunction in dcm’

A 45 year old man came with  recent onset breathlessness.His left ventricle was dilated along with left atrial enlargement.The LV EF was 42% (By current definition mid range preserved systolic function( Circ Heart Fail. 2016 Apr;9(4))

But, he was severely symptomatic because of combined  systolic and  diastolic dysfunction.Diagnosing and grading diastolic dysfunction has been extensively done in last decade.Now , we realise without significant diastolic dysfunction symptoms of pulmonary congestion can never occur in patients with DCM.

We don’t require complex tissue Doppler parameters to diagnose high-grade LV diastolic function.Just have a look at LA dimension,  concentrate the E to A ratio. A tall E that humbles the A by more than 2 to 3 times is clear evidence for  LA mean Pressure exceed  18 to 20 mmhg or so.

This , in combination with dilated LA is a marker of chronic severe diastolic dysfunction.The fact that A is diminutive in no way takes the Importance of Atrial contribution to LV filing at this critically compromised LV status.

Note E:A ratio is 3:1 .This simply means the early (and mid to a certain extent ) diastolic pressure in LA is high and most of the filling takes place before Atrial contraction .There is one more reason for diminutive A . Atrial contractility fails to prevail over E in late diastole as LV end diastolic pressure is significantly high in these patients with diastolic dysfunction.

A dilated left atrium is an Independent marker of significant LV diastolic dysfunction (In the absence of MR) .When does LA begin to enlarge in diastolic dysfunction ? There is uniform rule.Generally LA size more than 4.5cm indicate grade 3 or 4 LV diastolic dysfunction.

LA size and Pulmonary congestion 

It’s a paradox , a roomy  LA dampens the LA pressure curve and A reversal into lungs may not happen.

*AF irony on A reversal

Logic might suggest , loss of atrial contraction might attenuate A reversal and less blood flooding into pulmonary veins.No, It doesn’t happen that way.If  AF is precipitated for any reason its going to be “switch on”  for acute pulmonary edema.

What is the relation between systolic and diastolic dysfunction in DCM ?

We find about 30 % of DCM has documented resting diastolic dysfunction.This is actually a underestimation of true diastolic dysfunction as it can very well manifest only during exertion.

Though generally , there is good correlation of grade of diastolic and systolic dysfunction in terms of severity , some of the patients show severe diastolic dysfunction out of proportion with systolic dysfunction.

Note : In the above patient it’s actually a fairly preserved systolic function but still has advanced diastolic dysfunction.

Grading of diastolic dysfunction .Image courtesy MM Redfield et al: JAMA 289:194, 2003. Note E:A >1.5 is

Final message

Relying on E:A ratio to diagnose diastolic dysfunction  may appear  amateurish for some of us .The rampant reporting of E>A for grade 1 diastolic dysfunction has made this parameter a “Doppler cliché”. But , the fact of the matter is,  it does help us confirm severe (Grade 4) diastolic dysfunction when E stands  tall and towering over an almost dwarfed A.

Clinical Implication

Please realise ,In patients with DCM  when you find an  A that is too diminutive in combination with  a menacingly tall E , it may be prudent to raise diuretic dosage. It’s a sure signal for impending pulmonary edema.

Queued queries 

Can DT and IVRT normalise with progressive diastolic dysfunction ?

(more…)

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Pulmonary  arterial hypertension (PAH ) is  an uncommon manifestation of dilated cardiomyopathy .While pulmonary venous hypertension of some degree is expected in most patients with DCM,  it is rare for these patients to go for severe arterial hypertension.

The reason for this may be the  natural history of DCM do not allow these patients to live that longer to manifest severe PAH.  Still ,  we encounter this problem  atleast in tertiary hospitals. Presence of moderate to severe PAH (> 50mm peak PAP) is a sinister sign in  DCM. They not only do badly , they also make  the transplant outcome dismal .

What causes this severe   PAH in DCM ?  The following observations are made in our institute .

Now we know , isolated  systolic dysfunction is  rarely associated with PAH  .It is the presence of  LV diastolic dysfunction (Often restrictive )  that raises the pulmonary pressures.  PAH of DCM is rarely progressive.

One important suggestion is the DCMs  which are associated with  severe  PAH may indeed represent  late stages of RCM , when the LV begin to dilate.

Associated mitral regurgitation   contributes  to PAH

Atrial fibrillation has a significant impact on elevating  pulmonary  venous and arterial  pressures in DCM.

Hypoxic PAH can occur in any medical situation  in susceptible population . DCM is no exception

For some reason  idiopathic DCM is more often result in PAH than ischemic DCM . (Is that possibel , some form of  idiopathic   PAH and DCM are etiologically  related ?)

Further , the positive inotropic agents when liberally used will worsen the diastolic  properties of LV.

Finally involvement of  right ventricle  in the cardiomyopathy  process can have an ameliorating effect on PAH.  A good RV function is essential to lift the PA systolic pressure. If RV failure is causing a low PAP , do not be happy .It simply means RV is going to  say  good bye  . . .  for the final  time !

How to manage PAH in DCM ?

There is no specific management strategy .

We do not know yet  whether Sildenafil ,  Bosentan, and Epoprostenol  have any role in this  form of  PAH. These are all basically vasodilators. It’s use in DCM is vested with a risk of  catastrophic hypotension . Of course ,  we do have a role for balanced vasodilators in cardiac failure .(As most of these patients would be already on adequate ACEI )

Presence of PAH should be considered as an independent indication for anticoagulants as in situ  pulmonary thrombus is common.

The effect of  cardiac resynchronisation therapy in reducing the PAH of DCM is not convincing.

Final message

PAH  in DCM is an unwelcome development. It makes the situation  tough .  The mechanisms are diverse  .Understanding the mechanism would help us deal  this problem better .  Conventional anti failure treatment may help  ,but  it is wiser to try  reserve drugs.

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