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Archive for December, 2008

 Selected on the basis of ,  impact  on survival , relief of  human suffering index and also innovation

10.Percuateneous interventions

9.  Electrocardiography

8 . Hemodynamics of cardiovascular system

7.Fruesemide

6.Thrombolysis

5.Pacemakers

4.Defibrillation

3.Heparin

2.Prosthetic valves

1.Coronary care units

 

Waiting list

Concept of vascular biology

Statins

RF ablation

Nitric oxide

Total Artifitial heart

Echocardiography

 

Ten least important concepts and  inventions in cardiology

Selected based on duplication of research, futile scientific concepts and   of course impact on survival

10.Low molecular weight heparins

9.Cardiac resynchronisation

8.Rotablator

7.Multi  chamber pacing

6.Newer ARBs

5.C reactive protein

4.Three dimensional echocardiography

3.

Comments welcome  and please contibute

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A poorly deployed drug eluting stent is far inferior to a properly deployed bare metal stents

  • Doing a plain old balloon  angioplasty ( POBA)  is not a scientific crime , millions of coronary lesion just  need that! ( Click here -Why POBA is important ? )
  • PCI is most effective during an ACS than a chronic coronary syndrome
  • Primary PCI is a race against time and muscle , not a race against money ! Don’t do it  for a  evolved   MI
  • Recognise , from the patient point of view  the term no reflow is  generally  synonymous with   failed primary PCI( It is semantics !)
  • Side branch  can be more important than main branches , so don’t sacrifice it often
  • Attempting a trifurcation  angioplasty is generally not in  the interest of the patient but  to show interventional expertise
  • Make sure surgical back up means, a table is reserved with a surgeon fully informed and ready

When in  doubt , it is always  better to err on a longer stent than a shorter one

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ecg-ventriculophasic-21

Ventriculophasic sinus arrhythmia is a non-respiratory sinus arrhythmia seen in complete AV block.

The PP interval enclosing a QRS complex is shorter than a PP interval not enclosing a QRS.

The Mechanism 

ecg-ventriculophasic-sinus-arrhytmia1

The proposed mechanism is the  increased blood flow into the SA node artery  during ventricular systole  stimulating it to produce an early pacemaker activity and thus shortening the sinus cycle length.

Clinical significance : None for the patient  Academic purpose for the students

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The irony of medicine is unlimited !  100 years of active clinical  research   failed  to find a specific cure for the rhino virus mediated common cold.In fact  US Govt stopped funding for this .

While ,   complete cure is possible  for many of the cancers, especially hematological ones !

Message 

In medicine there are thousands  of disorder  which have no cure ! 

Cancers ,  constitute  only a  fraction of  them !

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coronary-artery1

                                                      Coronary arterial circulation is the life line for  the human heart  and it’s survival.Typically it is supplied by two coronary arteries,  left and right coronary artery.Both, together carry about  250ml of blood every minute.( Approxinately  equal to a  cup of  coke !  ).These coronary arteries  generally divide in a predetermined  fashion , and have multiple branches . It is a  mystery , what  decides this  branching pattern

Is it like a our palmar crease  ? or the cerebral gyri ?

However , it does follow a certain rule,  one major coronary artery  will follow the  four  important grooves of heart. In the left side ,  left main coronary artery (LM) originates in the left coronary sinus (Size varying between 1mm -20mm)  and usually bifurcates into LAD and LCX. The left anterior descending artery (LAD) runs in anterior interventricular  groove while ,  the right atrio ventriculo groove carries the right coronary artery(RCA) .Left  circumflex artery (LCX) traverses the  left atrio ventricular groove.The most inconstant branch is the posterior descending artery (PDA) which runs in the posterior interventricular  groove.PDA  can arise from either RCA, LCX or both or even from LAD.

The major branches of LAD are called diagonal and septal  while the branches of LCX are called obtuse marginal(OM).There can be two to three diagonal and OMs. 

What is ramus intermedius coronary artery ? What is the incidence of Ramus ?

The left main coronary artery  instead of bifurcating into two ,  it trifurcates into three vessels.(LAD, LCX, Ramus)

The real incidence could vary betweenn (10% to 30%) depending upon the series.

ramus

What course it takes ?

It generally goes in the angle between the LAD and the LCX.It may either behave like a large OM or a diagonal branch.It supplies the lateral free wall of the LV many times.The peculiarity of this vessel is it does not run in a anatomical groove .It simply slides over the free surface of LV.Rarely, a  very abnormal course of ramus,  criss cross the aorta and pulmonary artery .

How common is atherosclerosis within  Ramus ?

We don’t know yet. But it is very likely since it is an early branch from left main, it  might  have a  predilection for atherosclerosis  as like LAD or LCX ostium.In fact now we recognise more of  trifurcation lesions involving  three branches of left main .

What would be the ECG finding if a large ramus is the culpirit vessel during STEMI ?

This scenario could be rare.

ACS in ramus could  present as ST elevation in 1/Avl /V5,V6

  • Lateral MI
  • Apical MI
  • High lateral MI

But it is realised , whenever the ECG changes are not fitting with typical ASMI or a lateral MI one should suspect a ramus lesion

 What is the significance of ramus for an interventional cardiologist ?

ramus-2

                                                   PCI in ramus is a rare opportunity for a cardiologist .The issue here  is,  if ramus is involved  adjacent LAD and LCX is also likely to be involved .So it would logically be a multivessel , complex angioplasty.Isolated ramus lesion could be tackled easily.Another issue here could  be ,since this vessel is not within  any anatomical groove  stent deployment would have a poor  support and prone for mobilisation and migration .

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Stents are mechanical  devices like  a  spring ,  used to  keep an artery open after a PTCA or PCI.

des-why4

                                Bare metal stents(BMS) were found to have restenois rate of about 25%.  So it was perceived a stent should have it’s own protective coat , so that it won’t get restenosed.For this the researchers thought  anti cancer drugs are ideal as they block cell proliferation and thus neovascualrisation and restenosis.Alas, they were found dismally wrong ,  after all , neointiaml proliferation is only a part of the problem of restenosis  and simple blocking of cell growth is insufficient . The issue doesn’t stop with that, the anti cancer drugs incorporated within the stent simply can not differentiate normal from abnormal cells and

DES effectively blocks the normal endothelisation over the stents and make this highly vulnerable for acute stent thrombosis .

This complication is unique to DES and can result in SCD.Further ,during the last 6 years of DES , we recognised the restenosis rate has increased form the much hyped O % to almost 15% and it’s still growing . These  complications  has made a huge question mark over the future of drug eluting stents !

des-coverage

The concept of DES may not die , but which drug it should elute should be answered ! This  again is  going to be a long battle. So it is currently   adviced,  based  on common sense ( With due respects to  those RCTs  funded by industry )

Whenever you encounter a block within the coronary artery* Ask the following  questions in sequence  ,

  • Whether we can leave it alone  with medical therapy  ,  if the answer is no , proceed  to the next step !
  • Is there a possibility for plain balloon angioplasty in a given vessel (POBA, Yes !  the concept is not dead yet !)
  • If you decide a stent is required , Will  the  bare metal  do the job ?
  • In multivessel CAD  , Did the issue of increased metal load on the  long term outcome was considered ?
  • If lesions appear complex,  should we  not strongly consider CABG as an option ?

However  if we  have the habit of  ask ing the following  question  you are likely to deviate from scientific approach  

Is it possible to put a stent  across  the block ?

Yes , will be the answer most of the time ,and the patient will invariably get one or more stents  and carry a life long  stent related problems.

*The rule does not apply in Acute coronary syndromes

Also read this letter  posted by the author published in  British medical journal

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                                      One of the important principles of  post PCI care is,   we need  to be very careful  till the metal struts are fully endothelialised . This is of vital importance as improper endothelialisation  is a powerful trigger and nidus for a  imminent thrombosis and  acute coronary syndrome.

stent

It is a billion dollor irony , the much hyped DES does exactly what we don’t want ! and still it’s  usage is  increasing world wide .  The drugs (Anti cancer agents)  which coat the DES   are the villains as it  prevents  the  metal struts  from being endothelialised  and  keep the metal surface  raw and vulnerable , while the  much maligned  bare metal stents allow  this natural endothelialisation  process  without any interruption ! So right now it is mandatory  to administer dual antiplatelet agents  life long( life of the stent !)   for the patients with DES.

 Just look , at the following image of  a stent in vitro at  30 days follow up

des

des-2

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