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Archive for July, 2011

Poor R Wave in precardial leads would indicate old anterior MI , why can’t poor R waves in inferior leads reflect inferior MI ?

Posted in Cardiology - Clinical, cardiology -ECG, cardiology -Therapeutics, Cardiology -unresolved questions, Uncategorized, tagged , , , , , , , , , , , , , , on July 17, 2011| 1 Comment »

Can you diagnose inferior MI with poor R waves ?

No , you need  a “Q ” that’s  for sure !   Do not diagnose inferior MI without a  q wave  . ( The luxury of diagnosing MI without q waves  is available  only for LAD region )

Any axis deviation ( even 30 degrees) from  base line  can alter the inferior lead qrs morphology to a great extent. R wave amplitude is  primarily determined by the  initial septal depolarisation .  So if the  inferior septum is intact  it will never allow to inscribe a q wave  . Further ,  limb leads are bi polar leads and they are   sum-mated  potential  reflected along the entire  bottom half of the  torso . Hence it is not  reliable to attribute  significance  to presence or absence of  r wave (Unlike  chest leads).

The lung and diaphragm  exert  not only electrical insulation but   also mechanical  alteration of septal profile with phases  of respiration.

Counter point

Not really  . . .  you do not need a  Q   waves  to diagnose inferior MI  ,  electrically  diminutive R  is same as  “Q”

There is  an alternate way of  reasoning  too  . R wave is muscle , We diagnose LVH with tall  R waves so muscle loss should be equivalent to R wave loss .We have innumerable examples where  low voltage R waves are  recorded in inferior leads after a well documented inferior MI.

How do you diagnose old inferior MI by ECG ?

  1. Near normal ECG with degeneration of q waves and regeneration* of  R waves
  2. Residual T wave inversion
  3. Simple low voltage inferior leads
  4. Slurred or notched qrs  complex in 2 3 AVF
  5. Rarely with atrial abnormalities and AV nodal prolongations

The concept of regenerated R is well established . And it brings to the age-old debate of R with live muscle Q is dead muscle

Regeneration is salvaged muscle (Natural salvage , awakening from hibernation etc)

How good is Echocardiogram in diagnosing old Inferior MIs ?

Surprisingly , echocardiography do not help much either .Technically inferior transmural MI  is expected to  leave  a residual wall motion defect.  But many times it do not. Many non q inferior MI (Is there such an entity ?)  do look perfectly normal by echo .

The primary reason  for this is ,  infero-posterior surface is anatomically remote and it makes  wall motion analysis difficult .Newer tissue motion analysis (Velocity vector imaging)  could aid us better.

Some times a trivial or mild  mitral regurgitation is the only sign of   old inferior MI  as  the pap  muscle  lags behind in it’s  functional recovery  while  free posterior wall is  fully salvaged and contracting well .

Final message

It needs  that extra bit of   of  knowledge to  expose  our ignorance.

Even in this  maddening   scientific  era  we have valid  reasons to  go back to fundamentals  of  R wave and Q  wave genesis in MI ,  where clarity  is lacking .

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When do you do surgery for cardiac myxoma after a stroke ?

Posted in cardiac surgery, Cardiology - Clinical, cardiology -Therapeutics, tagged , , , , , , , , on July 16, 2011| Leave a Comment »

Cardiac myxoma  is  an  infrequent cause of  stroke in young . LA myxoma is the commonest  tumor  that can partially dislodge to cause a stroke.

It is not necessarily a  tumor emboli that causes the stroke  , super added thrombus is   common in cerebral artery histological  studies. ( In fact , some have advocated successful thrombolysis for myxoma and stroke !)

When do intervene in stroke due to myxoma ?

Image  courtesy: http://www.medicalscale1.com

As soon as cardiac  myxoma is diagnosed by echocardiography  it is customary to call the cardiac surgeons for their  opinion and feasibility of removing the tumor  at the earliest.

Myxomas need not be removed in an emergency surgery even if it has caused a stroke!

What is the optimal timing of cardiac  surgery in patients  with a cardiac cause of stroke ?

  • Stroke is a major vascular  event .Immediate cardiac  surgery is another major vascular  insult .
  • Extra corporeal circulation is known to affect cerebral perfusion  even in normal persons. In  patients with  acute stroke  this   can  have vital impact.
  • Anticoagulants used  peri -operatively  increase the risk of   converting  a simple stroke into hemorrhagic  one.

Hence , it is advisable to wait for 4 weeks after a stroke before removing the myxoma . One can not expect a controlled studyon this issue .  It  is to be  based on collective  experience of many.

Who should decide ?

A cardiologist, a cardiac surgeon and neurologist should  collectively decide along with patient’s input ( or his proxy)

When there is  a dispute in timing of surgery  Neurologists opinion shall prevail over others as the immediate concern is brain function.

Is there any  indication  at all for doing early surgery ?

High risk mobile tumors demand early removal as further strokes can be avoided. Individual discretion and institutional preferences apply.

Reference :

1 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2627525/pdf/TOCMJ-2-115.pdf

2.http://asianannals.ctsnetjournals.org/cgi/reprint/8/2/130

3.http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3064861/pdf/crn0003-0021.pdf

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200 years of Inappropriate cardiology care !

Posted in bio ethics, Cardiology - Clinical, Cardiology -Interventional -PCI, cardiology -Therapeutics, Cardiology -unresolved questions, Cardiology-Land mark studies, tagged , , on July 14, 2011| Leave a Comment »

It was  the year 1812 ,  exactly 100 years before the Titanic sank  over the Atlantic  , a  small bulletin from  Massachusetts General Hospital was  released .  It  later on became  the  single most  important  journal  for the medical community.  The appearance of  an article about  angina pectoris in the inaugural issue ,   reiterates the  importance of cardiology  even in those   days of primitive  medical care .

The volume. 1  : No. 1  issue of NEJM egan with a classical and critical observation of angina pectoris written  by Jhon Warren .

http://www.nejm.org/doi/pdf/10.1056/NEJM181201010010101

The first issue of NEJM . . . Witness to 200 years of medical excellence

Those were the days  when angina  was treated with tincture  opium and Fowler solution (Arsenic  potash ) .They  can be  termed as  height  of  inappropriateness  and  also  condemnable acts  . . .  is it not  ? 

200 years  later   . . .  in 2012  what  do you think has changed ,  in terms   of  appropriateness  of management   of angina pectoris  ?

What a surprise ,  two centuries  later ,  even as we are  treating  angina  in hi-tech cath labs  with bio-degradable stents and metabolic modulators   ,   bulk of our  population is  grappling with inappropriate therapy for angina pectoris .

Today ,patients are subjected to  questionable modalities  in the management of CAD ,  which the following paper   tries to expose !

Keeping the inappropriate flag high . . .200 years later in 2012


What a way to progress in Medicine !  The reason for this  “200 year  old ailment”  is  attributed to  extreme scarcity of common sense !

( A study , which says regular exercise  can be  as good as PTCA in multivessel CAD ,  would  sound  as a  “nonsense article”  for most  cardiologists  of  current  generation  !)

Finale

When we look  at human history , where billions  lived ( and continue to live ) in this  age old planet , it  would appear  a trivial matter  whether you treat angina pectoris with Tincture opium / Arsenical potash or  Prasugrel  / Rosuvsatin . . .

Whatever be the scientific advancement  the ultimate outcome on human health will depend on how we apply it. So, all young  medical fellows beware of this   !

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Pre-stenotic dilatation : Why do the coronary artery dilate proximal to an occlusion ? What is the clinical significance ?

Posted in Cardiology - Clinical, Cardiology -Interventional -PCI, cardiology -Therapeutics, Cardiology -unresolved questions, cardiology- coronary care, Cardiology-Coronary artery disese, tagged , , , , , , , on July 10, 2011| Leave a Comment »

Laws of fluid dynamics dictate there is a pressure drop across   a point of narrowing  and recovery  thereafter  . At  recovery point if the vessel wall is weak it tends to balloon out .This is called post- stenotic dilatation .This is  the anatomical equivalent of Bernoulli or venturi  effect. This theoretically  occur only distal to obstruction .

How do you explain the common observation of pre- stenotic dilatation?

  • Intimal weakening due to disease process is the prime  suspect.
  • Pre stenotic  increment in mean pressure  also play a role .
  • Mechanical distention due to stagnated blood  proximal to  critical obstruction  is  a  logical explanation.
  • Finally and most importantly ,contagious , sub – angiographic  atherosclerosis.

How is  dilatation  different from ectasia ?

May be they are all related phenomenon. The definitions  of ectasia ,  dilatation, aneurysm are  more to do  with semantics than with academics.

Clinical and hemodynamic implication in cath lab

  • Sluggish  flow prone for thrombus
  • Stent selection errors likely
  • Stent dislodgment  and migration

Long term effects

  • In stent re-stenosis is more common if adjacent segment show dilatation.

Finale

Enlargement of vessel wall in both pre and post stenotic segments are possible . In small vessels pre- stenotic dilatation is  more common , while in large vessels post stenotic dilatation is  more prevalent .(Aorta, Pulmonary artery)  The mechanisms are slightly different. Apart from the lesion tightness ,  hemodynamic  and genetic factors are also responsible These dilatations are  often labeled as ectasia in coronary artery  and  most cardiologists  tend to   ignore this finding especially if  the margins are smooth.

But , newer imaging modalities like IVUS, OCT have given   better  insight about these dilatations.These   are  actually an  expression  of the  contagious  atherosclerosis .  Pre-  stenotic segments are prone for extensive disease  than even the diseased segment due to  more hemodynamic turbulence. There is some evidence atherosclerosis progresses  proximally more than distally.Smooth margins within the  pre -stenotic dilatation  does  not guarantee  disease free status.

During PCI  there could be  an  argument for covering the dilated  pre- and post stenotic segments  as well* . (We vouch for endovascular stenting when aorta is dilated why  do we hesitate  in coronary  ?)  .Careful selection of  coronary stent size  is  recommended  and  allowance should be given  for these two (Pre and post coronary dilatation ) patho -anatomic phenomenon.

* Stent missing a lesion is stylishly called geographical  miss ! This should logically include dilated segments also.

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How to rule out critical left main or proximal LAD disease with near 100% specificity without coronary angiogram ?

Posted in Cardiology - Clinical, Cardiology -Interventional -PCI, cardiology -Therapeutics, Cardiology -unresolved questions, tagged , , , , , , , , , , , , on July 10, 2011| 4 Comments »

Very often in clinical  practice  cardiologists are asked to R/O significant coronary artery disease in asymptomatic persons .This population includes  people with multiple risk factors like diabetes, HT dyslipidemia  and non specific ST/T changes in ECG.

Many of us have lost the confidence of   ruling out CAD   in these population without looking at their  coronary angiogram.

Is it a right way of practicing cardiology ?

What we need to realise is,  we are asked  to rule out any critical lesions that are going to make a impact on these  other wise comfortable patients.  Nothing wrong if you miss a 30% lesion in PDA or OMs or diagonals !

Can we do this without doing coronary angiogram ?

Yes ,  we can .

Step by step  Ask these questions

  1. Ask the patient , if  he /she   can climb three  flight of  stairs  without any difficulty or
  2. Walk briskly for  20 minutes (5km/hr)

If yes , give  a   certificate   that he  has no critical  left main or proximal LAD  disease.

If you do not believe in his words , put him on a tread mill ,  if he crosses   stage  3   Bruce in TMT ( 9 mts)

give the above certificate  “with a frame”  now .

For still suspicious  physicians ,  We have  one more  investigation called  echocardiography !

Echo : The forgotten tool  for screening left main lesion.

Modern day echo machines have a  3mm resolution power (Many have 2mm ) .While ,  we are expected to look for 3mm vegetation to R/O Infective endocarditis , rarely is  a  cardiologist ,  tuned to  look for the left main ostium  in routine echocardiography  which averages 4-5mm is size. (Left main by echo link to another article)

In short axis  view just tilt at the level of pulmonary valves  (Atrio- pulmonary sulcus) one can visualise the left main ostium and the proximal left main emerging from the 4 o clock position. If you are lucky you can see the entire left main.

If nothing satisfies the physician (Or the patient)  ,Refer him for sliced CT scan , catheter coronary angiogram , or a  nuclear Imaging .Be ready for the attendant anxiety, interpretation errors, corporate  pressures , urge to  balloon ,  kick backs etc etc

By the way , how can  one  be happy by ruling out only left main disease ?  Is it not other lesions possible ?

Experience (Not science) has taught us  no  critical coronary obstruction is  possible ,  if  a patient walks for  9 minutes  in treadmill (10METS).

Even if it is there (A remote chance)  there is little documented benefit of any revascularisation procedure.

Counter point ?

Is it not a “crazy idea“  to rely on patients history in ruling out  CAD   in these era , where   angiograms relayed  live  into   cardiologists  ipad  ?

Science has no value if it is not applied  for the patients welfare. Meticulous clinical  examination (And application of mind)  is the foundation stone on which  any medical investigation and therapy  should be based  upon. Most of the inappropriate coronary revascularisation are due to  neglect   of  this vital  component of clinical examination.

(I wonder ,  is it  really possible  these ” acts of omission”   be  deliberate some times  ! )

Final message

Clinical interrogation  may  miss an insignificant  CAD  ,  but it can never miss a critical CAD* .

 

Do not do coronary angiogram routinely to R/O  CAD.

It is not the way cardiology is to be practiced !

If only we apply  those  simple,  time tested concepts in every day practice we not only  save millions of  Rupees ,   but also thousands of futile   diagnostic tests and associated untoward effects can be avoided.

* Senstivity of  ruling out any CAD is about 70% , but it’s capcity to R/O critical CAD approaches 100%.

Reference:

Please refer your own Brain.

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How useful is balloon atrial septostomy in refractory pulmonary hypertension ?

Posted in Cardiology - Clinical, cardiology -congenital heart disease, Cardiology -Interventional -PCI, cardiology -Therapeutics, Cardiology-Land mark studies, tagged , , , , , , on July 6, 2011| Leave a Comment »

Management of  severe  pulmonary hypertension continues to be a difficult task .Medical therapy is not definitive, in-spite of the new prostocyclins, endothelin antagonists and  sildenafil analogues.Natural history  depends mainly on  the presence of  any treatable cause ( Especially ,connective tissue disorders)  ,  supportive management along with anticoagulation.

Ultimate  strategy  would involve a   plan  for a “Lung “or  “Heart -Lung”transplantation  , if feasible. Last decade saw an innovative modality of creating an  artificial inter atrial  shunt to decompress the right heart .This had varied response in the  real world  , still  most  showed some benefit .In fact , in 1998 the world symposium on PHT ,  formulated guidelines for BAS (Balloon atrial septostomy)

Principle of  Balloon atrial septostomy (BAS)  and mechanism of benefit

The symptomatology  of  pulmonary HT  is largely  determined by mean RA pressure .

Puncturing  the  IAS and diverting blood  flow into left atrium would decompress the RA ( or even the RV )  and reduce the Mean RAP.

The resultant  right to left to shunt  can   increase the cardiac output  only  slightly ,  still  good enough to  provide   relief from the fatigue.(Though at the cost of  desaturation.)

What is the risk involved in the BAS.

Procedural risk of  a cath study in a sick  patient with hypertensive lungs (Can be really high !)

In some patients  even a small  fall in systemic  oxygen saturation can be counter productive.

What is the balloon used ?

Mansfield or Tyshak balloons are good choices .

Balloon diameters are between 5 -14 mm

Technique

Involves standard Brockenborough needle /Mullin sheath /Guide wire in pulmonary vein.

Atrial anatomy to  be well  analysed prior to BAS  . (Please note even though it is similar to PTMC , anatomically we encounter a large right atrium rather than left atrium .)

Fluroscopy with  TEE guide optimal

Pulmonary angiogram might help.

Intra-cardiac  Echo may be  ideal.

Blade septostomy may be preferred if hardware is available

The endpoint of procedure

  • Size of ASD > 5mm
  • Fall of arterial saturation < 80 %
  • Sustained atrial fibrillation with hypotension
  • Any  disabling complication

Hemodynamic impact

  • Cardiac output increase by 750 ml to 1 liter
  • It is expected ,  RA  mean pressure  would fall at least 5mmhg from  the baseline value.
  • PA pressure , no significant impact expected.
  • Tricuspid regurgitation regresses.
  • RA,RV size marginal reduction observed.

Follow up and outcome

  1. Greatest  relief is from syncope.
  2. Functional class improvement  in >50% .
  3. One year survival benefit is substantial (75-90%)  .Beats the  natural history (40%) convincingly.
  4. Late deterioration  can occur as ASD gets closed in few.

When  BAS is contraindicated ?

  1. Critical RV failure
  2. Patient in class 4
  3. Mean RA pressure > 20mmhg
  4. Pulmonary vascular resistance index> 55 Wood units / sq.meter

* BAV should not be considered as a  live saving  procedure  in any dying patient with PAH.  It needs to be  selected early and carefully .In fact,  the very high procedural complication  rate is related to late selection of patients.

Natural foramen  PFO better than BAV ?

We do not know yet.It is highly possible  natural opening up of PFO is good thing to happen for patients with severe pulmonary hypertension.

Reference

1 . SS Kothari  et all  Indian heart journal 2002

2. http://content.onlinejacc.org/cgi/reprint/32/2/297.pdf

3. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC484602/pdf/heart00028-0066.pdf

  4. http://erj.ersjournals.com/content/early/2011/02/24/09031936.00072210.abstract

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Why this article is vitally important for all Indian cardiologists?

Posted in Cardiology - Clinical, Cardiology-Land mark studies, myocardial disease, tagged , , , , on July 5, 2011| 1 Comment »

Tuberculosis is rampant in our country ( of course in any developing country ). Many of the patients who are referred  for cardiac  failure has history of pulmonary  tuberculosis.

In our echo lab we handle  100s of  patients every month from the regional TB sanatorium  . While the clinical presentation  mimics  COPD ,  many of them  have be severe bi-ventricular dysfunction  in echocardiography   and  bulk  of them satisfy the criteria for dilated cardiomyopathy . So what are we missing ? or guessing ?

The following paper  which  finds a  strikingly similar observation  . . .   is important for many reasons

  • It  comes for a prestigious Institute from India (PGIMS Chandigarh)
  • It strongly  suggest the link between DCM and tuberculosis
  • It also tells us both can be completely curable.

We know cardiac failure is a relentlessly progressive disease . We also know ,  certain forms  of DCM are reversible  especially infectious and toxic ones .Whenever we ask  our residents (Bitten by the western bug !)   for causes of reversible cardiomyoapthy  they promptly rattle out exotic conditions  like selenium deficiency and cobalt cardiomyopathy etc ,

  we tend to forget  “a big possibility  of   tuberculosis”  as cause for reversible cardiomyopathy.

  Students are not be blamed ,we have never taught them to think  in Indian  perspective !

Finale

DCM is a biggest  cardiac problem in our country next only to CAD. While our country men suffer , we are perennially happy to  label  them    as  idiopathic DCM   ,  even as   we  continue to  loose our  precious time  every day ,   in  ballooning dubious lesions  in  hi -tech cath labs  and help  fill the corporates coffers !

I entirely agree with the authors ,   DCM due to Tuberculosis  is  a hugely under-recognised entity  in a country with over  12o0 million people. So , youngsters  are  argued to find  answers to this   burning  issue . (* I am afraid how many of us are aware of such  an important  article published from India. )

We propose to under take a study from from Chennai  tuberculosis research center about this. Any body wishing to fund this project ?

How does tuberculosis affect heart muscle ?

Will be posted  soon .

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Can epicardial fat constrict the heart ? . . .An authentic “yes” from Ulsan , Korea !

Posted in Cardiology - Clinical, Cardiology-Land mark studies, Hemodynamics, Infrequently asked questions in cardiology (iFAQs), pericardial disease, tagged , , on July 4, 2011| Leave a Comment »

Constrictive pericarditis is a well known mechanical disorder  of heart that occurs due to the  compression  by thickened pericardium .Constrictive pericarditis is  the classical cause for  severe diastolic dysfunction.

We know , lungs are   prone for restrictive disorders due to chest wall , skeletal  disorders. Does the heart get mechanically restricted in extreme obesity ?

Not really , one may reason out . Chest wall fat can have little effect on cardiac function but when excess fat accumulates within the layers of heart , it is indeed possible for  the  fatty layer to impede mechanical filling of heart. This may be considered rare as of now , but many times it is not recognised ,  as most of the dyspnea in morbid obesity is attributed to some other known factors.

Dyspnea in obestity  can  due to

  • Pulmonary hypoventilation
  • Increased  MVO2 due to elevated cardiac mass
  • Diastolic dysfunction of  LV/RV
  • Increased demand  due to  excess BMI.

Image courtesey : http://www.onlinejacc.org

Now, we have evidence for  altered RV hemodynamics due to compressing effect  of epicardial fat pad. It may be due to   simple mechanical effect  of epicardial  fat over the distensiblity of RV or occasionally  LV. (The distribution of epicardial fat is mainly over the right ventricle or septal areas.)

This   paper  from Korean circulatory journal  succinctly describes this new possibility .

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2771803/pdf/kcj-39-116.pdf

Final message

Bed side cardiology  continues to  bring surprises  , it  never fails to fascinate us   !

Heart  is  a dynamic organ ,  has a potential to get restricted by  any  layer that  surrounds  it. Constriction by pericardium got huge attention so far .We need to realise , the epicardium which is  a part of pericardium has a variable fat depot  . It  can take a different avatar  in an occasional obese individual  and   exert  important hemodynamic impact.

Excess fat is excess load on heart . . .  we have  to unload it

It is possible , sucking out the  epicardial  fat in morbid obesity can bring important relief to  those patients with unexplained dyspnea . We  need to  explore this possibility.

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Is that a knot in the left internal mamary artey ?

Posted in cardiac surgery, tagged , , , , , on July 3, 2011| Leave a Comment »

LIMA is a critical conduit for CABG.It  is  the most suitable vessel for  CABG for various reasons.(Radial artery falls far short of expectations  due to anatomical and histological , physiological  reasons !)

Anatomical variations , kinks and bends , loops are more common in LIMA  than we recognise.This may not have major implication but  can be threat to it’s  hemodynamic superiority  .

This man who had a two loops in LIMA and the one above almost tied a knot .(Please note it is an end on view of a loop that mimic a knot )

Can a surgeon un-do the loop before grafting ?

It may be possible in the distal ends where the LIMA is dissected out. I dont think it would be possible high up.

Surgeons should answer this . . .

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Stock market fluctuations as triggers for acute myocardial infarction !

Posted in Cardiology - Clinical, cardiology -congenital heart disease, cardiology -Therapeutics, Cardiology -unresolved questions, tagged , , , , on July 3, 2011| Leave a Comment »

Myocardial infarction is the self-inflicted ,  modern-day death sentence  especially  among the  young generation who are   addicted to the affluent life style .

We know the  cardio vascular events  are  precipitated  due to a  sudden trigger in those  people  who have a base line risk profile. The major  risk factors are ,

  • Diabetes
  • Smoking
  • Hyperlipidemia
  • Hyper tension
  • Obesity

When one or more of the above factors   progress unabated he or she is at high risk for acute coronary event .

Is that a fatal stock market rhythm !

A loaded gun  needs a trigger to fire  , similarly  in a vulnerable patient (Plaque )  any of the following can act as a  trigger to precipitate an MI.

  • Hemodynamic stress (Fall or raise of BP )
  • Any  systemic illness( fever etc)
  • Physical stress
  • Mental stress , any strong surge of  emotion (Negative or positive)*
  • Non cardiac surgery

*Anger, fear , euphoria , guilt , bereavement ,

Now there is evidence pouring in  ,   natural calamities (  perceived fear of death) can  act as trigger  for MI.

We have reports  of  excess cardiac events   following  . . .

  • Earth quakes
  • Terrorist attacks
  • Flight scares

Any events which can release  sudden pulse of adrenaline into the plaques can trigger an acute coronary event.

Now,  this study from Shangai ,  documents how the coronary events dance to the tunes of stock market movements in the financial capital of  China .

http://eurheartj.oxfordjournals.org/content/32/8/1006.abstract

Final message

Chaos theory states no two events are isolated in this world  !   When stock market swings it can  pull down your heart too .

be cautious !

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