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Infective endocarditis continues to be a challenge for the cardiac physicians.

While we have innovated too much( More than what is required !)  in the interventional arena little is progressed in the last few decades on  this vital  area  of  “Infections of heart”.

Globally , deaths continue to occur in prime ages due to rampant infections of the heart valves.

Prevention of IE was recently deglamorised by diluting the criteria for prophylaxis by ACC/AHA (Cost issues ,  overwhelming science ? )

So, what is left in the war against IE ?

Early diagnosis and recognition

How to diagnose it early ?

Suspicion is the key  . . .

When to suspect ?

Suspect in all with fever and h/o heart disease . So far  no case of afebrile IE reported !

Get rid of the common myths

  • You don’t require vegetations to diagnose IE
  • Blood culture need not be positive
  • Fever can be low grade
  • Rarely severe fatigue is the only sign

This effectively means , one can diagnose IE without a major criteria of Dukes.

One can diagnose IE with 5 minor criterias

If you wait for a major criteria to develop to start treatment , it could be a  costly miss .

So have a open mind, suspect IE, treat early.

Do not unduly worry about , overuse of antibiotics in case of  false diagnose of IE.This  attempt is worth in weight  of gold !


Million ton of antibitics are used indiscrininately in this world by all walks of physcinas for simple cold and surgeions  non existing peripopertaive infections .

While , the global medical community has  accepted this concept with total submission (Intentional harm condoned !) , it is funny to ask for 100% appropriateness in the therapy for a  deadly infection of heart.

It is absolute necessity  to  inject an  anticipatory antibiotic in all cases of suspected IE with high risk valve lesions. (Of course ,  it need to be a reasonably appropriate antibiotic with microbiologists consultation to avoid interference in the subsequent culture evaluation !)

Minor only infective endocarditis.

Please note IE can be diagnosed with the following 5 minor criteria

  1. Predisposing lesion
  2. Fever >38c
  3. Immunological / Vascular lesion
  4. Culture eqivocal
  5. No clear cut vegetation , but high suggestion of vegetaion, New valve regurgitation

A related article in this blog

Vegetation negative infective endocarditis .

Final message

Never hesitate to start empirical antibiotic therapy in suspected high risk IE

Let us err . . . for the patient’s sake  !

Fever + New murmur*= IE until proven otherwise (Oxford handbook of  clinical medicine  P 136 7th Edition )

*It can be read as , presumably new murmur to increase the sensitivity.

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Patent foramen ovale is probably  the commonest  congenital heart defect.  (Bicuspid aortic valve will run close to it ! )

Note : PFOs  cannot be  called as a  true disease , since it is a  benign anatomical defect with little or no hemodynamic impact.

Consider  this scenario . . .

The incidence  of PFO could be as high as 20% of adult population. It means nearly 100 crore people of this planet  will suffer from this entity !

When does it become significant ?

Paradoxical embolism : In young persons with cerbro vascular accident , PFO s are more commonly observed , implicating some form form of venous to arterial embolus .

In some persons it is believed , it can shunt few CC of blood from right atrium to left atrium at times of right atrial hemodynamic stress. Like severe physical  straining  (valsalva like )

In seriously ill ventilated patients  PFOs can worsen the  hypoxia especially with  PAPP  mode .

When does it become a life saving savior ?

  • In patients with DTGV and intact IAS  even a a small PFO can sustain a life  till , emergency surgery or intervention is done .
  • In patients  with severe  pulmonary hypertension the PFO may act like a safety valve, opening at a critical moment and decompress the  right atrium and which  indirectly relieves  the RV wall stress as well .

Fancy relationships

Now , it is  considered PFO  is related to migraine by some means ! ( What means !)  The belief has strong evidence base that has lead  the aggressive  interventional cardiologists to  find a new hole to close  . This indication ,  if  approved will have a perennial supply of patients  as there are 100 crores of them .

How will you differentiate a PFO from a small ASD ?

Size alone can be a useful pointer in differentiating a ASD from PFO.

A PFO can  measure  between  2 to 10mm  ( most measuring between 4-6mm diameter)

Size matters !  The upper limit of PFO is the lower limit of ASD .

Practical experience suggest any defect  above 7mm should alert  us about the possibility of true ASD.

Other useful clues

  • PFO are always restrictive  (Use pulse doppler probe right across the PFO /ASD in subcostal view .If you pick up a gradient > 4mmhg (velocity 1 m /sec) PFO is confirmed.
  • Most ASDs do not show any significant  gradient
  • Right ventricle and right atrium should be normal in PFO  (Unless due to some other cause )
  • Doppler flow across  pulmonary valve can be very useful . If it exceeds 1.5m/sec , left to right  shunting is likely to be significant and PFO is unlikely.

Is there an entity called restrictive ostium secundum ASD ?

If so ,  how will you  differentiate it from PFO ?

Yes , we have ,especially in  cyanotic heart disease

Like TGA , Ebstien etc .

Isolated restrictive secundum ASD is extremely rare .

* There is no way to differentiate a restrictive ASD from a similar sized PFO .

What is the role of TEE in diagnosing PFO

It has a major  role in delineating the IAS anatomy .

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Coarctation of aorta  continues to be an  important  acyanotic heart disease  . Now , early recognition  and intervention  is possible with the availability of sophisticated imaging and interventional modalities.

Our understanding of this  entity , even though appears complete  . . . it  is not ,   especially the complexities of the collateral  circulation and the associated malformation.Even in this 21 st century , unexpected circulatory  compromise are reported in the postoperative phase from various vascular  beds (Spinal, mesentric, limbs etc)

It is also  surprising to note ,  much innocuous entities like  ASDs ,VSDs  have  popular  anatomical and functional classification.It is a  rare excercise ,  for cardiology fellows  to classify co-arctation of aorta .This ,  in spite of the fact,  we have a  meticulous classification suggested by Amato , way back in 1991  published in Annals of thoracic surgery .

Let us  be  aware of this  . . .  Click  the link below for Amato’s classification

Amato’s  surgical classification of  coarctation of aorta

Type 1  Primary Aortic Coarctation

Type 2 Coarctation with Isthmus  hypoplasia

Type 3 Coarctation with Tubular hypoplasia of distal arch

3A- With VSD

3B-With complex LV outflow lesions

* Ideally  we need to include BCAV and status of ductus , suitability of aortic stenting in the classification.

Other old classifications

Bonnet’s classification 

Infantile :which later became known as pre-ductal, and adult which later became known as post-ductal . These became obsolete , as we came to know all coarctation or juxta-ductal .(Very difficult to separate into pre or post ductal coarctation  by simply  looking at it  , without knowing the hemodynamics )

Conte et all      **  Backer

1.Isolated coarctation  2.Co- arctation with  VSD 3.Co arctation with complex heart anomalies.

  

//

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Aortic hypoplasia is a common observation in many congenital heart diseases  especially  acyanotic CHD. It is  important  to know the adequacy of systemic blood flow , in left-sided embryonic flow  defects like , co- arctation of aorta, interrupted aortic arch, shone’s complex etc .

The hypoplasia is thought to be due to two mechnaisms

1. Low flow state in utero( fetal heart) and the  resultant hypoplasia.

2.Ductal tissue migration into adjacent arch  which leads to  friendly arch  contraction !  when the  PDA gets closed

in the immediate new born period .

When do you suspect aortic hypoplasia ?

There is no strict definition available.But the Becker’s  data base provides a working rule.

Hypoplasia is diagnosed when ,

  • Isthmus is , < 40 % of  diameter of ascending aorta
  • Proximal  transverse arch  is ,  < 60 %  diameter of ascending aorta
  • Distal transverse aortic arch is , < 50%  of diameter of ascending aorta

Why ascending aorta is taken as reference ?

It is least likely to affected by the shrinking ductal tissue . Descending aorta can be a reference but it is at a  remote location and difficult to image .

Reference

Becker’s  CHD nomenclature and data base project . Annals of thoracic surgery  2000

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It is a well known  cardiac auscultatory  sign,   S 1  becomes  variable in intensity with the onset of atrial fibrillation.

In physiology , the intensity of S 1 is determined by many factors.

  1. The valve morphology(Thickness, Calcium , Rigidity )
  2. Valve mobility
  3. PR interval
  4. Force of LV contraction
  5. Preceding RR interval (4 and 5 are inter related)
  6. Insulation and auditory factors (Thick chest wall  etc)

How does atrial fibrillation modify the intensity of  S1 ?

It is to be noted , atrial fibrillation alters only one  of the above factors, namely the RR interval which becomes irregular.

The mix of short and long RR intervals  occurs at random  . A short RR interval, results in a relatively softer S1  and vice versa . The mechanism is directly attributable  to the degree of LV filling and subsequent change in force of contraction .

Many times , at fast ventricular  rates (Say >150) the distinction between short- long cycles is  negligible in terms of net cardiac cycle.

If  the RR interval , is too prolonged there can be an  inverse relationship  with s 1 intensity .It gets  muffled as the  mitral valve floats back  to it’s  orifice and a partial or even complete  closure occurs , making  force of LV contraction irrelevant in the genesis of S1 .

The vanishing act of PR interval  in atrial fibrillation.

It does not require great brains  to  understand ,  if P waves are absent ,  PR interval must also be absent !

If PR interval is absent ,  there  can be no  influence of it on the first heart sound. Logic demands  absence of PR interval must have some sort of  influence on the intensity of S1. As far as i know cardiology  literature has not answered this query.

What are the two types of S 1 variation ?

Experince  has shown us , the variation of S1 can be of two types*.

Sequence 1 : Varying between , Loud -Louder- Loudest -pounding

Sequence 2: Varying between , Loud -Normal – soft -Muffled

* Applicable only for those with shrewed ears !

S 1 intensity with reference to underlying pathology : Valvular vs Non valvular atrial fibrillation

It is obvious the impact of  varying RR interval on  the intensity of S1 will directly depend upon the underlying pathology. The  intensity of   S1  in  non valvular AF (Like , lone AF, Thyrotoxic AF, Hypoxic  AF ,Ischemic AF etc)  are  more vulnerable to  changing   RR interval .

In rheumatic heart disease , the influence of valve morphology , rigidness, calcification and presence  of MR  generally prevail over the  impact  of changing RR interval .So,  in a case of tight mitral stenosis  and AF  it  is expected the sequence 1 is more common .

In lone AF or AF due to CAD , sequence  2 is more likely *  Associated LV dysfunction , and ischemic   MR may further dampen the intensity of  S1 .

Clinical implication

Hearing  few occasional  loud  S1 in AF , is an indirect indication that underlying LV function is good,  as it reflects the force of  LV contraction .

Silent AF

Some hearts are notoriously silent even in the midst of AF. If  the silence is not  due to obesity  or  other insulation defects,  it suggests a sinister diagnosis ,  like severely  dysfunctional ventricle  like  DCM etc.

As a corollary, it is often noticed ,  palpitations* are , often not  felt  by patients with dysfunctional  ventricles  in spite of atrial fibrillation. (As loud S 1 is rare with dysfunctional ventricle)

*Palpitation is a symptom that equates to Dp/Dt of ventricles.

What  happens to mid diastolic murmur in AF ?

The murmur length  varies  linearly with reference  to RR interval. The pre systolic  accentuation disappears ,but   pre-systolic component may persist .

Final message

Simple, bed side auscultation during atrial fibrillation can give us vital clues about the etiology, and the  underlying LV function .  Let us not be ashamed to talk about clinical cardiology  . . .at least in the bed side !

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There are thousands of forums for medical science.

Most are aimed at research.  Few are available  to scrutinize  research.

Cardiac safety research consortium

This one from Duke university ,  is a great beginning in collaboration with FDA .

Let us welcome , this whole heartedly and wish all success in it’s motto !

Namely , exposing all safety issues in the modern cardiac therapeutics .

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This article is in response to the prevalent belief  about  primary PCI for STEMI   endorsed by world cardiology forums. (Caution: A highly personalized version)

Time window in STEMI

  • Is the window half-opened  or half closed ?
  • Is it open at all ?
  • Or ,does it open only for primary PCI  ,and tend to close down  bluntly for thrombolysis

Modern medicine   grew faster than our thoughts .We have witnessed the audacity of advising  arm-chair treatment  for MI  till later half of   last century . Now we are talking about  air dropping of patients   over the  cath lab  roofs  for primary PCI.

Still ,we have not conquered the STEMI. While ,  we have learnt to “defy  deathin many patients  with cardiogenic shock , we continue to lose patients(“Invite death “)  in  some innocuous forms  of ACS due to procedural  complications  and inappropriate ( rather ignorant !) case selection.

Note : The ignorance  is not in   individual physician mind ,   it is prevalent in the whole cardiology knowledge pool.

The  crux of the issue for modern medicine is ,  how to reduce risk  in patients who are at  high risk and how not to convert a low risk patient into a high risk patient by the frightening medical gadgets.

In other  words ,  arm chair treatment for STEMI was  not (Still it is not !) a dustbin management . It has a potential to save  70 lives  out of 100. What many would  consider it as  ,  nothing but  the natural history of MI .

Medical management of STEMI is ridiculous !

That’s what a section of  cardiologists try to project by distorting the already flawed evidence base in cardiology. Some think it is equal  to no treatment. Here we fail to realise, even doing none has potential to save 70 lifes out of 100 in STEMI who reach the hospital.

Out of the  remaining , 10 lives   are saved by aspirin heparin (ISIS 2) and the concept of coronary  care . Another  7  lives are saved by thrombolysis (GUSTO,GISSI) . PCI  is shown to save saves one more life (PAMI).The remaining 6-7 % will die in CCU  irrespective of what we do .

Of course , now medical management has vastly improved since those days  .  A  thrombolysed ,  heparinsed ,  aspirinised ,  stanised  with adequately antagonized   adrenergic ,  angiotensin system   and   a proper coronary care ( That takes care electrical  short-circuiting  of heart)   will score  over interventional approach in vast majority of STEMI patients.

Now comes the real challenge . . .

When those 70 patients who are likely to survive  , “even a arm-chair treatment“, and the 20 other patients  who will  do a wonderful recovery with CCU care ,  enter  the cath lab  some times in wee hours of morning  . . .what happens  ?

What are the chances  of   a patient  who would otherwise be saved by an arm-chair treatment be  killed by vagaries of  cath lab  violence  ?(With due apologies ,statistics reveal  for every competent cath-lab   there are at least  10  incompetent  ones  world over !)

In the parlance of criminology , a hard core criminal may escape from  legal or illegal shoot out  but an innocent should  not die in cross fire , similarly ,  a cardiogenic shock patient with recurrent  VF  is  afford to lose his  life , but it is  a major medical crime to  lose a simple branch vessel  STEMI (PDA,OM,RCA )  to die in the cath lab,  whom in all probability  would have survived  the arm chair treatment.

Why this pessimistic view against primary PCI  ?

Yes, because  it  has potential to save  many lives  !

Time and again ,  we have  witnessed  lose of   many lifes  in many  popular hospitals in  India ,  where a   low risk MI  was  immediately  converted  to a high risk MI  after an primary  PCI with number of complications .

I strongly believe I have saved 100s of patients  with  low risk MIs by not  doing  for primary  PCI in the last  two decades.

*The argument that PCI confers better LV function and longterm  beneficial effect is also not very convincing for low risk MIs .This will be addressed separately

The demise of comparative efficacy research.

Primary PCI is superior to thrombolysis  : It is agreed , it may be  fact in academic sense .

Experience has taught us , academics rarely succeeds in the bed side.

“superiority studies can never be equated  with comparable efficacy”

Only the  questions remain . . .

  • Where  is comparative efficacy  studies in STEMI ?(Read NEJM article )
  • Why we have not developed a risk based model  when formulating guidelines for   primary PCI ?
  • Is primary PCI for a PDA /D1/OM infarct worth same as PCI for left main ?
  • Is high volume center guarantee  best outcomes ?

Who is preventing comparative efficacy studies ?

Primary PCI : Still  struggling !

This study from the archives  of internal medicine tells   us , we are still scratching  the tips  of  iceberg (Iceberg  ? or Is it something else ?)  of  primary  PCI

Even a  pessimistic approach can be  more scientific  than a optimistic  !

When WHO can be influenzed and make a pseudo emergency pandemic  and pharma companies  make a quick 10 billion bucks  ,  Realise how easy  it is  for the   smaller ,  mainstream cardiology literature  to be  hijacked and contaminated .

Final message

Why we reverently follow the time window for thrombolysis,  while  we rarely apply it for PCI ?   This is  triumph of glamor over truth . The open artery hypothesis remains   in a  hypothetical state with no solid proof  for over 2o years since it was proposed.

Apply your mind in every  patient , do a conscious decision  to either thrombolyse  ,  PCI or none . All the three are  equally powerful approaches in tackling a STEMI , depending upon the time they present .Remember , the third modality of therapy comes free of cost !

Never think ,   just because  some one  has  an access to a sophisticated cath lab 24/7   , has a iberty to overlook the  concept of time window  !

Remember  you can’t  resuscitate   dead myocytes , however advanced your enthusiasm and   interventions are !

Realise , common sense is the most uncommon sense in this hyped up human infested planet.

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VSD is  the leading  cause  of   congential heart disease .

  • The natural history is hugely variable spectrum , from totally asymptomatic  , incidentally detected in   childhood to a fulminant cardiac failure  and death in early  infancy .
  • Many small VSDs get closed by year 10. None of the large VSDs close spontaneously.Few of the moderate sized VSD may get closed.
  • The site of the VSD is a major determinant of spontaneous closure. Muscular  VSDs are more likely to get closed .Of course many of the membranous VSD have  at least a rim formed by a adjoining muscular septum
  • Associated defects, RVOT obstruction and late onset AR also has a  influence  on the natural history.
  • Progressive PHT  leading onto   Eisenmenger  syndrome  occurs  has become a diagnostic curiosity in many countries .

It  is natural to expect  the VSDs   to share a  close relationship with  the conduction system which   fights for  “equal rights”  to occupy the inter ventricular  septum  , (In spite of   a defective septum ! )

How often we see conduction defect in VSDs ?

It is  rather surprising  to note   conduction  defects are not  common in VSDs .In fact it can be termed  rare . How  this is  posssible ?   VSDs , however large it maybe   ,  usually spares the conduction system . This is simply due to the fact , developmentally the two systems  , ventricular septum and the electrical  system  of the heart comes from different embryological focus and and are simply anchored together.

If the IVS is not formed properly ,the bundle  of His and it ‘ s major right and left branches  are  simply displaced  and not are  destroyed  ,  they  tend to occupy  one of the rims of VSD

*Further, a VSD located peripherally and distally towards the apex has little impact on the conduction tissue as it has already fanned out and small little twigs are affected ,while central , proximal,  and basal VSDs  can have more significance .

Classically ,  it has  major  significance   for the  surgeons than cardiologists  , as post operative blocks are more common than the preoperative blocks !

What are the  changes to the conduction system in various VSDs ?

Membranous VSD

  • Migration  of  A-V node   posteriorly toward crux of heart *
  • His bundle  courses  along  the  posteroinferior rim of defect

* This makes sure the compact AV node never comes into picture of VSD . It  also it explains the  rairty of   complete heart block  due to mechanical damage  to the  AV node  by the  VSD jet

How to avoid  injury during surgery ?

Sutures  are  made a few millimeters from postero-inferior rim,  Do not penetrate  the septum.  Suture along  RV side  of the  septum  as the  His bundle  is  often located on the  LV side of muscular septum.

RV approach to close VSDs,  make  postoperative RBBB a common issue but generally it has no great clinical significance

Location of conduction defect in various  VSDs

  • Membranous VSD  –  Conduction tissue runs along posteroinferior border of defect
    Muscular VSD
  • (Especailly with Inlet extension)  – conduction tissue is anterosuperior to defect
  • AV canal defects . This is the only type of VSD where serious defects of conduction occur  .Interruptions can also occur in the AV node.

Coming  soon . . .

Where  will the conduction system run in single ventricle where there is no IVS ?

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Many believe  modern science is pure and uncontaminated.

I wish it to be true ,  But reality mirror tells a different story !

The following  “spheres of knowledge”  collectively  form the  cardiology literature .

How much ?  each sphere , contribute is any body’s guess !

The same  rule might  apply  in all  medical  specialties.

Readers are argued to add more spheres of  knowledge.

The seventh sphere may be Eg :  “Commerce based cardiology “

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The funny thing in medicine is  ,   simpler the  question ,   greater the  difficulty to answer ! f  Clopidogrel  is   an  irreversible blocker of platelet aggregation . It  probably ,  is one  of the top  cardiovascular  drugs  used currently .It came into human domain as an aspirin killer and failed miserably , and currently piggy packing on the ageless aspirin for it ‘s action. The concept of dual antiplatelet agent is a classical example . The fact  that , Clopidogrel can rarely be used as a successful  mono anti platelet agent while aspirin can do this job with flying colors will unmask the secrets of  antiplatelet drug industry .

Do you know ,  this drug which  is considered  as a   great  antiplatelet drug , does  not even, pass the  basic test of   prolonging  the bleeding time  in a consistent fashion  ?

Still , we are not clear why it  does  or does not increase the bleeding time in vitro or vivo in linear  fashion.We have  confirmed this  in simple bedside experiments. (More dogmatic conclusions   can be drawn  in bed side , than those  double-blind studies) . In many patients 300 mg of clopidogrel failed to prolong the bleeding time even by  few seconds ! Surgeons who operate on clopdogelised patients differ  widely in their  experience  when they do emergency surgeries on them .

The issue is very vital  ,  Questions raised  are  critical  !

  • If clopidgorel  has a  notoriously unpredictable impact on prolonging  bleeding  time , Then ,  is it not  dangerous ? ,  for those millions of patients with DES(Drug eluting stents )  who live at at the  mercy of clopidogrel’s   erratic behavior.
  • Cardiology community  never got shocked  ,  even as  in this era of evidence based cardiology , a drug  which is being used for over 10 years without even a basic monitoring strategy for it’s efficacy.
  • Such is the scenario ,  it is not at all a surprise ,   to find a huge population  of DES patients   who  dial 911 or 108  with   sub-acute sent thrombosis  due to  clopidogrel failure and resistance.

Read this article published in one of the prestigious cardio thoracic  journal and comprehend  yourself   about clopidogrel’s controversy .

Final message

End of life , is  looming large on Clopidogrel , but it has done it’ s intended mission : Increasing the basic cost of cardiovascular   care in general population  .

A costly and a   dubious equivalent to  Aspirin   wrote a  phenomenal    success story in the narrow lanes of  medical wall street !

No doubt , it   will face the same fate as Ticlopidine ,   Prasugrel has just landed to repeat the same old story !

The easiest   job  to do  in   this wold is to fooling around   the public

and  it is an  irony medical professionals  and their patients  are  often

the   victims

Read also the herd mentality in  medical science

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