Dr.S.Venkatesan MD

Regulating the regulators !

September 24, 2010 by dr s venkatesan

The world of medical science is moving in a alarming speed.In any field , speed is always dangerous ! That’s why we have speed breakers , traffic police , speed cameras , etc etc . The medical world is flooded with new devices, drugs , procedures . Though the mankind is benefited with many of them , a equal number could do the opposite.

How to identify which is causing benefit and which doing harm ?

It is a horrible fact , this is the most difficult exercise for the medical academia . . . Still worse , harm will masquerade as benefit ! Further , beneficial concepts are often buried alive if it lacks glamor or commercial value (Eg: The Digoxins,)

Lay public (as well as ) the physicians are fed with half-baked ( Often quarter baked !) medical information .Many of the medical journals, guidelines , sponsored seminars , some times even text books do a clandestine campaign . Even after a completion of major trial, real truths rarely come out . Funnily , they call them aptly , as blinded study ! Who is blinding whom is a different issue .

So , in this new millennium , thousands of innovations are on the pipeline. These pipes are often infested with trivial , duplicate or even harmful concepts waiting for a grand release into human domain.

Take the story of coronary stents

In 1977 , Gruntzig mastered the opening of the obstructed coronary arteries with a simple balloon without any add ons . That patient is still alive without angina . In the next 30 years we have ridiculed (Rather , we were compelled to ridicule it ! * Read the related article Is there a role for plain balloon angioplasty ?

Technology made it possible to introduce a gamut of intra coronary devices .We used (?abused ) all sort of anticancer drugs within the tender human coronary arteries .In 2002 , we claimed to have climbed the summit and conquered the restenosis with DES. And in 2010 , every one knows what is happening to DES .

The malaise is deep rooted in every specialty . Next came the Stem cell fiasco ? and more recently huge conflicts of interest exposed in the vaccines against H1NI

Final message

Who is going to regulate the menace ? Hmm . . . . then . . . Who will regulate the regulators ?

Is there a way out for our patients ? or they have to suffer with it along with the disease . The later is more realistic option !

Posted in bio ethics, cardiology-ethics, Infrequently asked questions in cardiology (iFAQs) | Tagged des, double blinded trial, drug eluting stents, drug regulation, ethics in cardiology, ethics in medicine, stents | Leave a Comment »

50th anniversary of cardiac resucitation had just gone by . . . silently !

September 23, 2010 by dr s venkatesan

In 1960 , exactly 50 years ago , a group of doctors from Jhon Hopkins published their observation in 20 cases. It went on to become , one of the most remarkable discovery in the history of cardiology .

They taught us how to use a pair of hand , as an artificial heart and save lives

They are . . .

Dr Kouwenhoven*
Dr James R. Jude, and
Dr G. Guy Knickerbocker .

* He was not a medical doctor but an electrical engineer at Hopkins but he worked in the medical school as well .

They meticulously documented , each patient’s case history , whom they were able to successfully revive , (It was in the same period , the AC/DC shock was also invented in the Hopkins ) .One of the highlights of their paper was , with each chest compression they were able to elevate the carotid pressure up to 90mmhg and was recorded in a pressure tracing .

We have to thank the JAMA (Journal of American medial association ) for making this original article available free in their website .

Must read for every cardiologist

http://jama.ama-assn.org/cgi/reprint/173/10/1064?ijkey=33bb40fe3062331bae50e10c8a04263f3e26b317

Posted in Cardiology - Clinical, Cardiology-Land mark studies | Tagged cpr, jhon hopkins, Kouwenhoven | Leave a Comment »

Corrected transposition of great arteries :A rare review article !

September 14, 2010 by dr s venkatesan

In this era of technology hype , cardiology journals are flooded with interventional articles. Congenital heart disease has been pushed to the back ground . CTGV* is a fascinating congenital heart disease (Of course ,not so fascinating for the patient !)

*TGV and TGA are used interchangeably .

It is a complex disorder of ventricular looping (L Looped ventricle LTGA )

This can occur in three forms

Isolated CTGV
CTGV with VSD or PS
CTGV as a part of complex cyanotic heart disease.

The irony of this disorder is , it has two errors in development that tend to neutralise the hemodynamic abnormality .

ventricular connection is abnormal (Discordant) . RA is connected to LV and LA connected to RV . Still nothing alarming happens as LV is connected to Pulmonary artery and RV is connected to Aorta .(Ventriculo arterial discordance)

In spite of this natural hemodynamic correction , one can not ignore this entity ! as it is anatomically uncorrected for the rest of the life.

Since morphologic RV acts as a systemic ventricle it is bound to have difficulty in tackling the systemic pressure in later in life .

Further , the two complex defects called (also called as ventricular inversion ) make sure that the conduction tissue and the AV valves are distorted and squeezed in the AV junctional arena with it’s unique double looping defect .The his bundle inverses, the left AV valve often regurgitates .Complete heart block often ensues.

Management

Isolated CTGV are best left alone .
When VSD /PS are associated corrections are adviced
It is not simple surgery , one may require a technique called double switch .(I always wonder such surgeries are ever indicated in other wise asymptomatic population with isolated CTGV)

Here is an article from “The Heart” that deals with the problem of CTGV , may be . . . in a manner no other journal has ever done !

Congenitally corrected transposition of the great arteries Heart 2010;96:14 1154-1161

You need some luck to get a live full text link here

Posted in cardiology -congenital heart disease | Tagged atrioventricular discordance and ventriculoarterial discordance, complete heart block in ctgv, corrected transposition of great arteries, ctgv, double arterial switch, double av node, double discordance, double switch, his bundle inversion, left av valve regurgitation, levo transpostion, ltgv, ventricular inversion | Leave a Comment »

A new coronary risk factor : Community smoking

September 10, 2010 by dr s venkatesan

Coronary artery disease can be termed as “New age plague” afflicting the mankind ! It probably has killed ( or Killing ) as many lives as most other diseases put together. Why only a section of our population is vulnerable is not fully understood .

We are familiar with coronary risk factors for too long . . . still . . .

We do not understand why 50% CAD occur in people who have no known coronary risk factor !

There has been propositions and dispositions of various risk factors . The latest one is the Air pollution. This is quiet interesting, as air is the staple food of human survival . We eat , drink , (Rather inhale ) about 500 ml /of air every 3 to 4 seconds for 24 hours a day for 365 days , for our life time !

Does the air we breath reach the largest cardiovascular organ namely the vascular endothelium ?

Yes definitely , not only it reaches the endothelium but also injures it (When it contains gases other than oxygen ) .While tobacco is a well established endothelium destroyer , it is no surprise community smoking ( Air pollution !) will do the same job with perfection .

What are the proposed toxins in the air pollution that harm the endothelium ?

It is a mixed masala gas out there over our polluted cities ! .(Atmosphere, Industrial, Automative ,Domestic, Human , and other invisible sources ) We need to analyse further to answer this question authentically .

Though , common sense is enough to establish the link between air pollution and CAD. We have lots of evidence coming up . . .

Reference

http://ajrccm.atsjournals.org/cgi/reprint/173/4/432?maxtoshow=&hits=10&RESULTFORMAT=&titleabstract=coronary&searchid=1&FIRSTINDEX=0&resourcetype=HWCIT

Further research

We will be shortly reporting our experience with endothelial function assessment in traffic police population of our city Chennai ,India .

Posted in Cardiology - Clinical, Cardiology -unresolved questions | Tagged air pollution and cad, community smoking, new cad risk factor, passsive smoking, smoking and cad | 1 Comment »

In acute coronary syndrome , can you legally thrombolyse in the absence of ST elevation !

September 9, 2010 by dr s venkatesan

Thrombolysis is specifically indicated when there is ST elevation in ECG. ST elevation is a surrogate marker for total coronary occlusion. It occurs due to current of injury flowing towards* the lead facing the infarct territory . There is only one situation where you can safely and effectively administer thrombolysis in the presence of ST depression ie

Note : There is no accepted terminology to label a MI as ST depression MI . Here it is used to emphasise ST elevation is not the only indication for thrombolysis .In posterior MI there is infact ST elevation but it is failed to pick up by standard 12 lead ECG.

NSTEMI is a different entity altogether and thromolysis is never indicated.

Isolated ST depression in V1 V2 V3 .It almost always indicate isolated posterior STEMI. This can be confirmed by posterior chest ECG leads V7-V10 .

*One will be surprised, to know the mechanism of ST elevation in STEMI is still not fully elucidated .Technically speaking the net movement of current is away from electrode as there is only a baseline diastolic shift which gets neutralised in systole mimicking an ST elevation .(Electro-optical illusion !)

How sensitive is these leads to detect isolated posterior STEMI ?

Fairly sensitive. Both scapula and para spinal muscles can be a significant electrical barrier that can prevent ST elevation from inscribed .In case of doubtful ST elevation in posterior leads , mit is always better to rely on the clinical presentation.Acute chest pain , consistent with ACS and a new onset ST depression >2mm V1 to v3 is a definite indication for thrombolysis .

Link between posterior MI and RV MI ?

They are closely linked entities .In fact posterior surface of heart is contributed significantly by RV.

What is the angiographic correlation of isolated ST depression in V1 to V3 ?

It almost always localise the lesion to left circumflex artery . If it is dominant , it can involve lateral and RV territories.

Is isolated posterior MI less dangerous ?

May be yes , but only after the patient reaches the hospital as electrical risk is same in every STEMI .

The area of infarct is less , LV failure is less common. While conduction disorders and ischemic mitral regurgitation can occur significantly.

Also read , Why thrombolysis is contraindicated in UA/NSTEMI ? in this blog

Posted in cardiology- coronary care, Infrequently asked questions in cardiology (iFAQs) | Tagged isolated posterior mi, lcx stemi, posterior stemi, RVMI, thrombolysis for nstemi, thrombolysis in st depresion | Leave a Comment »

The “must read” books on Intra-operative transesophageal echo and mitral valve repair !

September 7, 2010 by dr s venkatesan

Mitral valve can be termed as the most important valve of heart . The reason for this : It is the only valve that is dependent on the Left ventricular function (The parameter which determines the ultimate outcome in any form CAD ! )

So , indirectly mitral valve function will invariably be affected by some degree at least in most patients with LV dysfunction. (After all LV free wall , is a component of mitral valve apparatus.)

While , we have numerous modalities to assess mitral valve function , the one that has fascinated the surgeons during mitral valve surgery is the intra operative TEE.

Many believe TEE provides live images of mitral valve which are not possible even under direct vision ! The eye of the TEE sees the mitral valve from a posterior location , (of -course It can see at any angle !) while surgeon can see in one angle . The types of repair , the adequacy of repair, the annulus status, even a trial mitral run , can be done with the help of TEE.

The TEE probe silently does this job sitting inside the esophagus , without obstructing the surgeon’s operative field .

The success of TEE as an investigative tool did not come easy.Decades of observation , innovation and learning( Especially from department of cardiac science Mayo clinic USA , where they standardized the views. ) are involved .

Now we have omni plane, real time 3D TEE probes .

The books which are considered the best for TEE aspects of mitral valve and it’s repair are

Posted in cardiac surgery, Cardiology - Clinical, echocardiography | Tagged echocardiogram, mitral, mitral valv e, mitral valve repair, tee, transesophageal echo | Leave a Comment »

The ultimate reference article about pathology of atrial myxomas !

September 6, 2010 by dr s venkatesan

Cardiac myxomas are rare tumors. But they present in a dramatic way. It can have severe systemic symptoms and present even as fever of unknown origin ! While , physicians of previous era were struggling to make a ante-mortem diagnosis we are blessed to make a instant diagnosis with echocardiography !

Want answers for all these from the original researchers ?

What is the pathology myxoma ?
What are the classical Locations ?
Difference between Sessile Vs pedunculated
Soft vs Hard
Benign vs malignant / Locally invasive
Recurrent myxomas
Vascularity of myxoma
Calcification (RA myxoma> La Myxoma)
Non atrial myxomas(Valvular papillary myxoma)
The Cell of origin (Stellate , polyhydral )

You will not get a better reference than the following article , including extensive illustrations . An 1980 article from Mayo clinic published in American journal of pathology

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1903582/pdf/amjpathol00223-0227.pdf

LA myxoma : A Video

A case reported from my hospital Hosted as Video presentation Follow the link

http://www.youtube.com/watch?v=SD2LrK1mdic&feature=related

Posted in Cardiology - Clinical, Cardiology-Land mark studies | Tagged LA myxoma, pedunculated la myxoma, sessile myxoma, tumor plop, tumors of heart | Leave a Comment »

The mystery drug called Ranalozine !

September 4, 2010 by dr s venkatesan

A drug with a peculiar mode of action is recently making waves across the globe (At least some parts of it !) Basically , when the world was looking for an anti anginal drug without much hemodynamic effects Trimetazidine fitted this slot .While it’s popularity soared in Europe and Japan , the Americans thought there was a need for a similar drug but supposedly different mechanism of action . Thus Ranalozine was born.It is a piperazine derivative.

How does Ranalozine act ?

There are three important actions for Ranlozine ( 4th one a real surprise !)

Antianginal
Anti arrhythmic
Possible lusiotropic effect
Anti diabetic*

*It is surprising to note Ranalozine was reducing Hb A1 c . This is incidental or a simple statistical fairy tale we do not know !

Anti anginal

It acts on the late Na ion channel in phase 2 of action potenial .
This facilitates excess Ca to be removed from the cells by the NA/Ca exchanger
Calcium exit improves ischemic myocyte’s metabolic performance as cell injury is prevented .

This makes this drug an effective anti anginal.

The MERLIN TIMI 36 in NSTEMI population became a big dampener against the enthusiasm for this drug.But it did not affect much the sale of the drug !

Antiarrhythmic

A drug , which acts on phase 2 Na channel , it is not at all a surprise to have anti arrhythmic properties .

It can reduce phase 2 reentry like EADS

pro-arrhythmic action

Paradoxically by blocking Na channels it stretches the phase 2 and hence QT interval is prolonged

Lusiotropic action

By preventing the calcium from accumulating from the cytosol it has a theoretical ! lusiotropic action.

It is funny , even theoretical action is enough , for many drugs to enter the standard cardiology literature !

What is major advantage of Ranalozine over other drugs ?

It virtually has no hemodyanmic effects .

Unlike other anti-arrhythmic drugs it acts , only if the late Na channels are abnormally active .

(Which is a case during episodes of ischemia .) This prevents QT interval to prolong in normal persons

In spite of all these meaningful actions and less side effects , FDA approval why cardiologists in the back of the mind think this drug is not based on strong scientific principles , and it could simply represent an industry sponsored placebo ?

I do not know the answer to this question , but I do share the same feeling.

Will it succeed the test of time ?

In this context , I recall a famous statement by my professor “A drug , which has least side effects , is very unlikely to have any desired effect also”

But with world , taking a commercial avatar a success of a drug lies , not in having a desired action but in how many million packs are ultimately sold in the market. It is akin to a bad movie succeeding phenomenally in box office while a good one lying silently unnoticed

Posted in cardiac drugs | Tagged late sodium ion blocker, merlin timi 36, metabolic modulators ion cad, ranalozine, trimetazidine | Leave a Comment »

A new “Avatar” in Jugular venous pulse examination

September 3, 2010 by dr s venkatesan

Looking at the neck veins for hours together has been a favorite pastime of our cardiology ancestors.Thanks to those sharp intellect , that has led us to this height of cardiovascular revolution. Measuring JV pressure by itself was considered a big science. Putting a patient in 45 degrees , marking the sternal angle, identify the oscillating venous column, measuring the vertical distance etc . . .

Now in 2010 , with bedside hand-held echo one can rapidly rule out an elevated central venous pressure by imaging the jugular vein directly . Here is an article from American heart journal

http://www.ncbi.nlm.nih.gov/pubmed/20211304

Simon MA, Kliner DE, Girod JP, et al. Detection of elevated right atrial pressure
using a simple bedside ultrasound measure. Am Heart J 2010; 159:421–427.

Soon , your mobile will double up as ultra-portable echocardiogram

Read this related article in this blog .

Coronary care in your pocket

Posted in Cardiology - Clinical | Tagged angle of lewis, cvp, jugular venous pressure, jugular venous pulse, sternal angle, two scale vs one scale in jvp, ultrasound and jvp, vertical column of blood | 2 Comments »