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Archive for the ‘Cardiology – Clinical’ Category

Who killed Starr -Edwards valve ?

Posted in cardiac surgery, Cardiology - Clinical, cardiology -Therapeutics, tagged , , , , , , , , , , , , on January 15, 2011| 5 Comments »

Prosthetic valve implantation has revolutionized the management of  valvular heart disease . The original concept valve  was a ball in a cage valve  , still considered as a  fascinating discovery.  It was conceived by the young Dr Starr and made by Engineer Edwards  .This was followed   by long hours of arguments,  debates and  experiments that ran into many months . The  silent corridors of  Oregon hospital Portland USA remain the only witness  to their hard work and motivation.  At last,  it happened , the first human valve was implanted in the year 1960. Since then . . . for nearly  50 years these valves  have done a seminal  job for the mankind.

With the advent of  disc valve and bi-leaflet valve in the  later decades of 20th century , we had to say a reluctant good-bye to this valve.

There is a  lingering question among many of the current generation cardiologists and surgeons why this valve became extinct ?

Starr and Edwards with their child !

We in India , are witnessing these old warrior inside the heart functioning for more than 30 years.From my institute of Madras medical college  which probably has inserted more Starr Edwards valve than any other  during the 1970s and 80s by Prof . Sadasivan , Solomon victor , and Vasudevan and others .

It is still a mystery why this valve lost its popularity and ultimately died a premature death.The modern hemodynamic  men  working from a theoretical labs thought  this valve was  hemodynamically  inferior. These Inferior valves worked  like a  power horse  inside the hearts  the poor Indian laborers  for over 30 years.

A Starr Edwards valve rocking inside the heart in mitral position

The cage which gives  a radial support* mimic  sub valvular apparatus, which none of the other valves can provide.

* Mitral  apparatus has 5 major  components. Annulus, leaflets, chordae, pap muscle, LV free wall.None of the artificial valves has all these components.  Though , we would love to have all of them technically it is simply not possible.  The metal cage of Starr Edwards  valve partially satisfies this  , as  it acts as a virtual sub valvular apparatus.Even though the cage has no contact with LV free wall, the mechano hydrolic  transduction of  LV forces to the annulus  is possible .

Further , the good hemodyanmics of this valve indicate , the cage ensures co axial blood  flow  across the mitral inflow throughout diastole. .Unlike the bi-leaflet valve ,  where the direction of  blood flow is determined by the quantum of leaflet excursion  in every beat . In bileaflet valves  each leaflet has independent determinants of valve  motion . In Starr Edwards valve the ball is the leaflet . In contrast to bi-leaflet valve , the contact area  of the  ball and the blood in Starr Edwards  is a smooth affair  and  ball makes sure  the LV forces are equally transmitted to it’s surface .

The superiority of bi-leaflet valves and disc valves  (Over ball and cage ) were  never proven convincingly in a randomized fashion . The other factor which pulled down this valve’s popularity was the supposedly high profile nature of this valve. LVOT tend to get narrowed in few undersized hearts.  This  can not be an  excuse , as no consistent  efforts were made to miniaturize this valve which is  distinctly possible.

Sudden deaths from  Starr Edwards valve  .

  • Almost unheard in our population.
  • The major reason  for the long durability of this valve is due to the  lack of  any metallic moving points .
  • Absence of hinge  in this  valve  confers  a huge mechanical  advantage with  no stress points.
  • A globe / or a ball  has  the universal hemodynamic advantage. This shape makes it difficult for thrombotic focus to stick and grow.

Final message

Science is considered as sacred as our religion .  Patients believe in us. We believe in science. A  good  durable valve  was  dumped from this world  for no good reason. If commerce is the  the main issue ( as many still believe it to be ! )  history will never  forgive those people who were  behind the murder of this innocent device.

Cardiologists and Cardio thoracic surgeons are equally culpable  for the pre- mature exit of this valve from human domain.  Why didn’t they protest ?  We  can get some solace  ,  if  only we can impress upon  the current valve manufacturers  to  give a fresh lease of life to this valve .

http://www.heartlungcirc.org/article/S1443-9506%2810%2900076-4/abstract

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Heart is like your Car : Do you need to service it periodically ?

Posted in Cardiology - Clinical, Cardiology -Interventional -PCI, cardiology innovation, tagged , , , , , , on January 15, 2011| Leave a Comment »

It is   surprising  to find  many   similarities between  our heart and the car .Both essentially carry out  mechanical function.  One carries the  life , while the  other beats ,  breaths life !

  • The car is the status symbol  of modern life  , while the heart is a life by itself .
  • The car has a 4 stroke engine  , while the heart has only two strokes – systole and diastole !
  • The car pumps petrol  , the heart does it with blood.
  • The car can afford to take rest at night in your garage   but  , your heart doesn’t.
  • Car  can be replaced  by a fresh one every 5 -10 years your heart can’t be.
  • In India  , it is  mandatory   for  the cars  to be  insured for  about  10 Lakh  rupees , while  the   poor hearts of our country men  are not even insured for a  single pie  !
  • A dent in your  new  Toyota  can give us   sleep less nights for many days .  A bruised and battered heart with tobacco and cholesterol is rarely  bothered about .

When the silent  screams of the heart  are not respected and heard ,   there is no other option left  for  it ,  to register its protest  , except with  a  heart attack   .This  can either be a  SOS call  or  a  call from  Heaven !

Final  message

Remember ,  the   heart breathes  your life ,  your car  doesn’t .Heart is   million times glorious than your car.

It is foolish to compare  the heart with a car . But let us  at least  learn to respect it  . . . like  our car.

Heart service station

  • Authorized heart service centers are few . Insist on genuine spare parts. Good  service engineers are becoming a rare breed.
  • Remember  both defective spare parts   and  dysfunctional service  engineers  can ruin your heart.
  • Do not allow your heart to  be explored and dismantled for flimsy reasons.
  • Never hand over your heart to strangers.
  • Do not-self indulge in 64 slices  of  fancy   shooting  of  your heart . Resist the temptation.
  • Finally do not ever go for unscheduled  free heart  service camps . That is the beginning of  trouble for your heart.

Some hearts  may  servicing alright , but realise , you are the master of the  service station .

If only you respect it , it  rarely requires to be sent to a  garage (cath lab )


Simple life style, adequate activity,   nutritious diet,  peaceful   sleep,  good work ethics ,respect to  fellow citizens  ,good-bye to  anger , helping the poor, a joyous family life , and finally  . . . less  visits to your physician  !  These  make  a  perfect , sure shot  recipe  for  living   100  glorious years !

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Sure shot recipe for living 100 years !

Posted in bio ethics, Cardiology - Clinical, medical quotes, tagged , , , , , , , , , on January 15, 2011| Leave a Comment »

Why is it .  .  .  so difficult ,  to  acquire  healthy   habits  and   good  behavior  in life ?

How to over come it ?

Answer :

No body can answer this question . . .Except yourself  !


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5 minutes crash course on Ventricular septal rupture !

Posted in cardiac surgery, Cardiology - Clinical, Cardiology -Interventional -PCI, cardiology -Therapeutics, Cardiology -unresolved questions, Echo library and gallery, echocardiography, myocardial disease, tagged , , , , , , , , , , , , , , , , , , on January 14, 2011| 2 Comments »

We know,  electrical deaths constitute the bulk of sudden cardiac deaths in MI.  Mechanical deaths due to pump failure, muscle rupture , valve leak , also cause significant deaths   .(Surprisingly many of the mechanical deaths   may also   fulfill  the sudden death criteria !)

Free wall rupture is  invariably a fatal event. Papillary  muscle trunk  rupture  leads to severe LVF and unless intervened sure to result in fatality.

The ones who tear their interventricular septum  are some what blessed ! Here ,  the rupture does not result in instant death as there is  no loss of blood ,   instead , there is an  volume over load of right ventricle  followed by the  left ventricle  after a  few beats. Hypotension is the  rule. Even though this is a major complication there is something about  VSR which makes it unique.

Sudden giving way of IVS has  a decompressing effect on the ailing left ventricle.This many times  bring a  temporary relief to LV and if the patient survives the first few hour he is likely to stabilise  further . In fact , sudden deaths within 24hours after the onset of VSR is an exception.This defect always gives the cardiologists and surgeon some time to plan the management. We need to use this time judiciously.

The natural history is delicate . Five themes are possible

  1. Very unstable – Instant death( Fortunately a  rare theme )
  2. Unstable – Deteriorating further
  3. Unstable to Stable * fit for discharge even without surgery
  4. Stable from the onset and  continue to be stable* .
  5. Stable to Unstable (Probably the most common theme )

* Pleasant themes occasionally witnessed !)

Here is 55 year old women came with extensive anterior MI with lower septal rupture.(She belonged to type 3 of the above scheme)

)

Note the septal rupture is visible even in 2D Echo

 

Color flow showing significant shunting from LV to RV.This shunt depends upon the LV contractile function, LVEDP and ofcourse the RV pressure

 

If there is severe RV dysfunction or bi ventricular dysfunction flow across the defect is inconspicuous.Brisk left to right shunting may be an indirect marker for good LV systolic function and absence of significant pulmonary hypertension.Both imply a better outcome.

The main determinant  of survival is the  underlying LV dysfunction and associated co morbidity(Renal function ) and complications .

Infero -posterior ruptures tend to be complex and  may have multiple irregular tracks  that makes it difficult to repair.

Investigations

Echo cardiogram is the mainstay .Serial echos should be done to assess the mechanical function and the progress of VSR.Hemodynamic monitoring may be done without injuring the patient .

Medical management

  • Often supportive , but  effective . Dobutamine infusion can maintain a life for few days.
  • Paradoxically , LV dysfunction and elevated LVEDP restricts volume overloading of VSD.
  • Associated MR, Arrhythmias  need to be taken care of .

Surgeons role

  • Very Vital.
  • Experience counts.(Individual as well as  Institutional )

Timing of surgery

Continues to be a controversy . Surgeons love to operate in a stable patient. But they need to realise , surgery is often needed to stabilise  many  patients. . The issue of tissue friability  is blown out of proportion in the literature .When a  life is  is at danger we can not worry about  friable tissues !

The rule of thumb could be

  • Operate as early as possible in unstable patient.
  • Post pone surgery in stable patient as late as possible ( Late here means . . .elective non emergent surgery )

Surgical options

  • Simple VSR closure without  knowing coronary anatomy
  • Simple VSR closure after knowing coronary anatomy
  • VSR closure with CABG ( total revascularization)
  • VSR closure with partial revascularization

In our experience  each of the above , has a role in a given patient depending upon the logistic , financial , social and even  the available expertise. (A good surgeon in bad Institution !)

Is coronary angiogram mandatory  before attempting to close VSR ?

Logically yes. If it is not available  just do not bother .  But, many times , when issue is saving lives , we can not afford to be too scientific , many lives have been saved by not following  such strict  protocols .A simple emergency  thoracotomy and closure of rupture site (Without even touching the LAD ) can be a distinct  and viable option in  a selected few .

Role of cardiologists

Contrary to the popular belief the role of cardiologists is minimal , except  to prepare  the patient and hand over to the surgeon.

Interventional approach to close  a VSR  is currently  be termed as an  adventurous option ! The VSRs  can assume unpredictable shapes  and the  tears can be multiple  in  different planes. The devices , catheters and  other hard ware are not specifically made to tackle these  issues  .An acquired VSR  should never be compared with congenital VSD.

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Newer observations about tall T waves in STEMI

Posted in Cardiology - Clinical, cardiology -ECG, Cardiology -Interventional -PCI, cardiology -Therapeutics, Cardiology -unresolved questions, tagged , , , , , , , , , , , , , on January 9, 2011| Leave a Comment »

T waves attract less  attention in STEMI ,except for the  fact   tall T waves  implies   hyper acute phase of  STEMI.

What is the duration of hyper acute phase ?

  1. Few seconds
  2. Few minutes
  3. An hour
  4. Few hours
  5. Any of the above

Answer

No one exactly knows  .It can  be highly variable .  So , 5  could be  the correct answer .  

 * Most importantly  hyper acute phase  need not occur in all patients with STEMI as suggested in experimental models.

Some  observations in T wave behavior in STEMI

Mechanism of hyper acute  T waves

It is the pottsium channel dynamics.Transient intracellular hyperkalemia  is thought to be responsible.

T wave as marker of  reperfusion

Inverted T wave in precordial leads are a good marker of IRA patency  especially in LAD

Slowly evolving STEMI

This is relatively  new concept . STEMI with a prolonged hyper acute phase  ,  ie ,  T waves ” dilly dallying”  for hours or even few days have been recognised. (This was  refered  to pre-infarction angina in the past )

This sort of T wave behavior makes it difficult to diagnose STEMI.Enzymes will help , still  thrombolytic guidelines  demand us to wait till ST elevation to occur. This is  unfortunate .But as physicians we are  justified to thrombolyse tall T waves with a clinical ACS .The other simple solution is to shift the patient to cath lab to find what exactly is happening in the LAD ! 

Now , what is new about  T waves in STEMI ?

It is  the localizing value  in LAD infarct

A tall persistent  hyper acute T wave  helps us to localise a LAD lesion .This paper from Netherlands ,  clearly  confirms this observation. The study was done from a primary PCI cohort,   a perfect setting to assess the  T wave behavior  in the early minutes /hours of  STEMI .

Other mysteries about T waves in STEMI

Does hyperacute T waves  occur in infero-posterior STEMI ?

I would believe it is very rare .Our CCU has not seen any tall T waves in inferior lead. Further analysis of the  data from the  above study could answer this question .

How often a  hyperacute T waves transform into NSTEMI ?

This again is not clear.Most of the hyper acute T will evolve as STEMI .But  , nothing prevents it to evolve as NSTEMI a well . After all , a hyper acute T   MI can  spontaneously lyse in a lucky few , ( Who has that critical  mass of natural  circulating TPA )  .If  these natural lytic forces are only partially successful , it may evolve into de nova NSTEMI.

Bi-phasic T waves in ACS.

A benign looking T waves with terminal negativity in precordial leads  can some times be a deadly marker of critical LAD disease.This has been notorious to cause deaths in young men which often correlates with the widow maker lesion in LAD.

What is a slowly evolving STEMI ?

Prolonged tall T wave phase  possibly   indicate , the myocardium is relatively resistant to hypoxic damage .

The most bizarre aspect in our understanding about ACS pathophysiology  is the concept of  time window , based on which , all our  ACS therapeutics revolve !

Does all myocardial   cells  have a same ischemic shelf  life ?  Can some patients  be  blessed with  resistant myocardial cells   when confronted with hypoxia or ischemia ?

                                 It is well-known  , in some hearts ,  the  muscles go for necrosis within  30 minutes of  ischemia,  while some hearts can not be infarcted even after 24 hours of occlusion .So , slowly evolving STEMI is a feature of  myocardial ischemic resistance .This is not  a new phenomenon as we have extensively studied about the concept   ischemic preconditioning .

We wonder there is something more to it . . .  the quantum of preconditioning  can be inherited .Further  , we are grossly ignorant about  the molecular secrets of  non ischemic metabolic  preconditioning  .

Final message

                         T waves attract less  attention in STEMI . Cardiologists are often tuned to look only the ST segment , after all ,  ACS  itself is classified based on  the behavior of this segment.(STEMI/NSTEMI) . We need to recognise ,there is a significant subset of ACS   affecting exclusively T waves.  Shall we call T elevation  MI ? ( TEMI )

Do not ignore T waves in STEMI. It has more hidden electrophysiological  treasures that  is waiting to be explored .

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Please welcome “Coronary calcium ” in non obstructive CAD !

Posted in Cardiology - Clinical, Cardiology -unresolved questions, cardiology- coronary care, Cardiology-Coronary artery disese, tagged , , , on January 5, 2011| 2 Comments »

Some say medicine is a funny science . . .  it is true  at times. It will remain so , as long as we convert  a fact into a myth and a myth into a fact at our convenience . It  is  often   fueled  by the  whims and fancies of modern research  ! This phenomenon is happening in a regular  fashion  for  many decades now.

The number one killer disease of heart  is  the atherosclerosis  . Atherosclerosis means hardening  of arteries. The advent of coronary  calcium score with CT scans ,  it became a craze among many physicians . (It was   replaced later  by 64 /128 slice MDCT with unprecedented  commercial over tones !)

How can we  conquer the atherosclerosis ?   when the enigma of calcium in coronary artery is yet  to be solved.

The next few decades will be crucial   as  we are  trying to find answer to the following question .

Is  coronary calcium  good ,  bad or neutral   in CAD  ?

This article in American journal article begins the new year 2011  with good news for people , who show some calcium in their plaques.

What makes a plaque vulnerable ?

Plaque contents , it’s distribution and consistency make it vulnerable. Soft spots  formed by   lipids   may  result in  plaque cracks and fissure.   Semi solid  , mixed  ,  gel like soft  plaques   are dangerously prone for  rupture . Oxidation of LDL,  LDL  liquefaction and tissue metalloprotinase , thickness of fibrin caps , all promote softening.  If none of above  mechanism is operative in a given patient , the   plaque becomes  stiff and hard.

Calcification is the ultimate in hardening . Calcified plaque  is resistant to mechanical deformation.If  stiff  plaques   are less vulnerable , hard plaques ( ie calcified  plaques ) must be least  vulnerable . Calcification   can be called an end result of coronary atherosclerosis.

So , calcified  coronary artery  can be referred to as  a failed  mission of  atherosclerosis .It is  equivalent to  death  of atherosclerosis and denotes the end process of this dreaded disease process.

Calcification tames atherosclerosis  in it’s own den

What is the implication of a stiff hard, sharp calcified plaque lining  (or even projecting ) in the coronary lumen ?

As this study has shown , calcium in the walls of coronary artery is innocuous  . Of course , calcium should not be dense and obstruct the blood flow . This will  require  intervention. Many  consider , calcium as  a foreign body in the coronary artery . But the prevalent understanding is ,  presence of non obstructive calcium  is often  a  non issue or in fact a welcome issue in some.

After all , millions of  human beings  happily roam around  with the hardest possible substance  lining their  coronary artery called  stents.

Caution about calcium

This article does not portray calcium as a healing molecule in  CAD . In  the realistic senseit is  too complex to make such a generalization.  The  message is  , calcified lesions are less likely to result in acute coronary  events than soft , non calcified lesions.

It is well known ,  calcium can be problematic for the interventional  cardiologists  .It makes life tough for them in deploying  stents. Calcium rich lesions exerts  radial force in a diagonally opposite direction and interferes with stent approximation.

It is also believed localised , sharp calcium crystals may tear a plaque  and cause   plaque dissections. This  happens if the calcium is lying in an eccentric fashion overhanging the shoulder region of the plaque   abutting a soft spot.

Final message

It is now clear ,  why calcium  score in CT scans  failed miserably to predict  high risk subsets of CAD. In spite of repeated studies  the researchers failed  to show a positive correlation .  The studies are flawed  as they  were trying to look for a positive correlation  which is non existent . In fact , the above study seems to suggest calcium  score may indeed  predict low risk individuals!

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How to calculate pulmonary vascular resistance without even touching a catheter ?

Posted in Cardiology - Clinical, cardiology -Therapeutics, Cardiology -unresolved questions, echocardiography, tagged , , , , , , , on December 27, 2010| Leave a Comment »

Calculating the pulmonary vascular  resistance (PVR)  has been a  big head ache for all those involved in pediatric and (for many )in adult cardiology as well  . The complex formulas , the delicate  oximeter samples, the catheters, a sick child , an arrhythmia prone right ventricle , restless staff  nurses , and  finally the mathematics  !  all make it a dreaded exercise .

Echo is a great physiological tool  . . . It is now been used  over 50 years . It is our earnest belief ,   Doppler can measure the flow and pressure any where within the heart   however dynamic  the chambers may be !

Then ,why can’t  we have a simple formula  by  this  non invasive method  to calculate PVR  ?

Yes ,  Dr Abbas et all  from the desert hospital  of Arizona  raised  this question and  reported a new equation to calculate PVR.

Their  hypothesis is as simple as this . . .

  • Pressure     =    Resistance X Flow
  • Resistance = Pressure /Flow

Pulmonary vascular resistance = PA Pressure/PA FLOW

Substitute PA pressure with TR jet

Substitute PA flow by   RVOT VTI (  Velocity time integral )

And  we  get

PVR = TR Jet velocity/ RVOT VTI x  10

This  is the simplest way to arrive at PVR at the bedside .

An example

Is it validated ?

Yes .

Then,why it is not being followed widely ?

It is  a  too  simple  method to  use   !  That  is  the biggest excuse ! We are tuned  to  think  ,  a  complex parameter can not be measured in a  simple manner  .  Any thing simple must be  wrong !

But the reality is  . . .

Cath calculations are   much more  complex with so many variables   which  can  get terribly wrong .

The irony  about this  hypothetical  science of PVR is ,  we do not know  which is  gold the standard ?   In fact , none can be  a standard .  So ,  to label PVR  derived by echo ,  as an   inferior modality  can not be accepted  .It is all the more funny ,  as  we are  trying to  define a new  formula    with  the help of   flawed and battered   parameter  namely  the cath derived PVR .

Final message

Abbas’s  formula  is  indeed a  realistic way of arriving at PVR by echocardiogram. If only we measure it routinely  /serially in as many patients as we can , a new data base  will  be created .Which can later be  proven as a fact.It is suggested every cath lab should try to validate this formula.

Link to full text article : Courtesy of JACC

Abbas AE, Fortuin FD, Schiller NB, Appleton CP, Moreno CA, Lester SJ. A simple method for noninvasive estimation of pulmonary vascular resistance. J Am Coll Cardiol 2003;41:1021-7.

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Land mark reviews in cardiology : How to choose an ideal coronary intervention in unstable angina ?

Posted in Cardiology - Clinical, Cardiology -Interventional -PCI, cardiology -Therapeutics, cardiology journals, cardiology- coronary care, Cardiology-Coronary artery disese, Cardiology-Land mark studies, tagged , , , , , , , , , , , , , , on December 18, 2010| Leave a Comment »

Cleveland clinic is a leading centre for cardiac care .Major technological breakthrough occurs from this institute than any other place. Thousands of articles come out every year. Some articles , get global attention and make  a huge impact. These are usually related to a new hi- tech modality like CRT devices or percutaneous aortic valve deployment etc ,etc.

                                                Some articles , which are very important  may not get the due  attention . Journal editorial boards often  have a scorecard called impact factor .That is ,   how  a  journal  is  impacting the practice habits of  medical professionals . Ideally we need to have to grade individual   articles with impact factor .Many articles may not have any significant  impact  however good the impact factor of the journal.

Here is an article,  which excellently depicts the principles of management of ACS.  It was published in 2003 JACC,  by Steven Nissen  from Cleveland,  Ohio .It deserves more attention . Every cardiologist , involved in ACS management should read this, especially the interventionist.

Link to article placed her with courtesey of JACC

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When “Atrium” outgrows “Ventricle” restrictive cardiomyopathy is diagnosed !

Posted in Cardiology - Clinical, cardiology -Therapeutics, Cardiology -unresolved questions, pericardial disease, tagged , , , , , , on December 12, 2010| Leave a Comment »

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A classical restrictive cardiomyopathy . Both atria balloon out as they face stiff resistance from the ventricles

Restrictive cardiomyopathy(RCM) is a common form of myocardial disease which was difficult to recognise  in the past.It was also commonly confused with constrictive pericarditis. Today , one can easily recognise this entity.A simple clue is bi- atrial enlargement  with relatively normal ventricle size.The above case is a classical form of RCM.

In late stages of RCM ,both LV, RV begins to dilate and can mimic a dilated cardiomyopathy. Doppler filling pattern  , and tissue Doppler motion of mitral annulus are recently validated methods to identify RCM. Still ,  2D features  are  very useful .This implies , the anatomical changes in the chamber size  are as important as physiological AV filling profiles. It is generally believed , physiological impairment precedes anatomical defects.( But not proven concept yet ! )

Note: The ventricles are not dilated and retain good systolic function

In the above patient  , etiology could not be confirmed and was labeled as idiopathic RCM  as tests for amyloid and eosinophilic infiltrations were negative.

M -Mode of the same patient confirms good systolic function

One would  call  for doppler mitral filling profile here ,  to confirm restrictive physiology ( A short DT , Short IVRT  . A reversal in  pulmonary veins , E/E’ ratio etc etc ) But all these are redundant here.

How is RCM different from non dilated cardiomyopathy ?

A new entity is being recognised in the cardiac  muscle disease.This is often referred to as NDCM (Non dilated cardiomyopathy)  .Global  systolic LV dysfunction  with normal  LV dimension.This a similar to the terminology MDCM (Minimally dilated  cardiomyopathy  where LV dimension increases  not more than  15 % of basal size ) .

This is seen in CKD and diabetic individuals.Atria may be enlarged .Diastolic dysfunction may co exist.  It is no surprise,  this entity closely mimics RCM. But in RCM LV systolic function  is not greatly compromised till late stages , while NDCM it begins with systolic dysfunction. This is the only difference .There can be overlaps .

Many strongly believe ,  both  RCM  and NDCM are one and the same entities ,  that present in different time frames in their natural history.

Final message

Diagnosing RCM is no longer difficult in established cases* . The message from  this article is , 2 D echo can  strongly suggest  the possibility of RCM (or even clinch it)  .  Never ever  diagnose RCM with normal 2 D echo. Doppler filling profiles are useful  additional tools . We  can not diagnose RCM with doppler features alone , but we can  be fairly certain about RCM when we encounter  typical bi-atrial enlargement and a normal LV by  2 D echo.

Caution : Patients  with longstanding atrial fibrillation of any cause , can dilate their atria and could mimic RCM .They can be some compromise in LV function due to chronic tachycardia .

* Recognizing RCM ,  very early in the course is still a problem . Here the  newer modalities like Phase  MRI, tissue doppler, speckle tracking, and velocity vector imaging may be useful.

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The conundrum called cardiomyopathy ! How is DCM different from RCM ,NDCM and MDCM ?

Posted in Cardiology - Clinical, Infrequently asked questions in cardiology (iFAQs), myocardial disease, pericardial disease, tagged , , , , , , on December 12, 2010| 2 Comments »

Dilated cardiomyopathy (DCM )  is the commonest  cardiac muscle disease .Diagnosis is simple and straight forward. All that we  require is,   documentation of LV dilatation and contractile dysfunction.The nomenclature of cardiomyopathy has remained a difficult exercise .This   is primarily  due to   iatrogenic  & intellectual confusion  among  cardiologists . They mixed up etiological and morphological entities together ,   later on  they  wanted to de-link  etiology from morphology  ,  ultimately they realised  when illness strikes the heart ,   it   can not differentiate the  morphology, etiology and pathology as we would want to   . So , whenever possible we have to label  cardiomyopathy with all components (Dilated cardiomyopathy due to alcohol with some restrictive features.)

This article  tries to evoke  some thoughts    about  why  LV dilatation  is central to the understanding of cardiomyopathy.

DCM is the prototype where LV dilates with global hypokinesia.The upper limit of   LV diameter is generally considered to be 56mm in diastole.  (Range 35 -56mm) .This cut off  point is too empirical  for the simple reason, the  left ventricle can dilate   up to  50 %  from it’s basal diameter and still technically  be within normal limits.( A 3.5 cm LV ( end diastolic diameter ) can dilate to 5.6 cm ,i e  a 50 % dilatation , still LV  has not reached the upper limit of normal  )

Even as we do not have a clear  answer to the above issue , we  recognise  left ventricle muscle can hypertrophy, progressively  dilate , transiently dilate, fail to  dilate ,  regressively  dilate  or  hypotrophy .These changes can be dynamic and heavily influenced by hemodynamic and local pathologic factors like fibrois, interstitial proliferation etc. Meanwhile , the pharmacological ,   surgical /catheter injuries we  inflict    , modifies  the muscle behavior in a positive or negative manner.

In this back ground ,  we have found a new entity called NDCM .

Apart from  DCM, a newer form of  cardiomyopathy  is being recognized  .This is often referred to as NDCM (Non dilated cardiomyopathy)  .Global  systolic LV dysfunction  with normal  LV dimension.This a similar to the terminology MDCM (Minimally/Mildly  dilated  cardiomyopathy  where LV dimension  do not  increase  beyond   15 %  upper limit of normal  ) .

This is seen in CKD and diabetic individuals.Atria may be enlarged .Diastolic dysfunction may co exist.  It is no surprise,  this entity closely mimics RCM. But in RCM LV systolic function  is not greatly compromised till the  late stages , while NDCM it begins with systolic dysfunction. This is the only difference .There can be overlaps .

MDCM was reported in 1990  . Keren gave a excellent insight about the condition  ,  It is unfortunate it failed to take off as a popular  clinical entity .  Cardiologists are argued to use this term liberally in their clinical practice .

Final message

Cardiology is not  that  simple as one would like to ! The two components of cardiomyopathy ie   LV dilatation and LV dysfunction can be temporally dissociated  one may precede the other. To  complicate the matter further, one of them may not manifest at all !

Few ,  still consider many of the RCMs and NDCM are one and the same entities that present in different time frames in their natural history.

So the simplified  concept  to decode the cardiomyopathy conundrum  could be

  • When both  dilatation and dysfunction occur it is classical DCM
  • When dysfunction  alone occur without dilatation it is NDCM
  • When both dysfunction  and dilatation are less it is RCM*(Relaxyl dysfunction must)
  • When dilatation is mild and dysfunction is severe it  is MDCM

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