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Archive for March, 2010

Great cardiology websites : This one is for cardiac radiology !

Posted in Uncategorized, tagged , on March 7, 2010| Leave a Comment »

Hunting for  treasures in medical jungle is no easy job

There are  thousands  of websites for learning  radiology  and then ,

This one  . . .

Hats  off  to   William Herring, MD,

http://www.learningradiology.com/toc/tocorgansystems/toccardiac.htm

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How to identify pulmonary veins in transthoracic echocardiography ?

Posted in Cardiology - Clinical, cardiology -congenital heart disease, echocardiography, Uncategorized, tagged , , , , , , , , , on March 6, 2010| Leave a Comment »

Even though it is a great vein , often the imaging pulmonary veins by echocardiography is a not a pleasant excercise.

This is due to the following facts

  • The pulmonary veins are posterior structures
  • They occupy the far field of echocardiographic window
  • The pulmonary veins often enter obliquely into the LA
  • The course of PVs are highly variable ( Like RCA origin !) especially in ASDs ,where identifying PVs becomes all the more important

Hence no fixed imaging angle can be advised . But generally a pattern is observed.

  • Right pulmonary veins are best viewed in apical 4 chamber or 5 chamber or in between (Especially RUPV is  seen best in 4.5 chamber view !)
  • Left pulmonary vein , can be seen in apical 4 chamber but best visualised in  Para sternal short axis view.

Other modalities for imaging pulmonary veins

TEE : Can be  very useful since it is brings the vein closer to the probe .But needs more expertice.

Contrast echo :Probably a simple and best modality often underutilised.

Very useful to clinch the diagnosis when PVs take abnormal course as in PAPVC .

MDCT , Spiral CT, MRI  are the new age modalities that can provide us  with dramatic  3d images of PVs.

The  echocardiogram will always prevail over these sophisticated gadgets for its simplicity and also it’s ability to give us the physiology of pulmonary venous flow which is vital in many diseases(Constriction, Diastolic function etc)

The following illustration is a gross attempt to simplify the imaging of PVs.Please note the rules may not be applicable in all.

Left upper and lower pulmonary veins in short axis view will be posted shortly .

Reference

The images are  based on  personal observations and  an  excellent insight  on the topic from  Department of Cardiovascular Medicine, Guangdong Provincial People’s Hospital, Guangzhou , China

http://ejechocard.oxfordjournals.org/content/9/5/655.full

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A landmark study , but least popular among the interventional cardiologists !

Posted in Cardiology - Clinical, Uncategorized, tagged on March 3, 2010| Leave a Comment »

Are the drug eluting stents really better than bare metal stents ?
A million dolor question ? , No . . . a billion dolor question
A study which answered most convincingly with a huge data base  published in LANCET 2007.
  • 38 trials  , Metaanalysis
  • 18 023 patients with
  • 4 year follow-up of up to 4 years.
  • No mortality difference from bare metal stent vs DES
But unfortunately there is  no takers for this  study . The usage of DES continue to  surge ahead  .
The problem facing the medical science in the current era
It takes years  of research to get  into  the truth    and  still   longer time  for  us  to  accept it ! Ironically  falsehoods have immediate patronage and there is no incubation period !

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What do we mean by membrane stabilising action of magnesium and lignocaine ?

Posted in Cardiology - Clinical, cardiology -Therapeutics, Infrequently asked questions in cardiology (iFAQs), tagged , , , , , , , , on March 3, 2010| Leave a Comment »

Human body is a collection of trillions of cells.  Life  is nothing but , a bundle of energy flowing across each of these cells  .Every  organ  has a  specailised mode of communication among themselves and others. When a cell is in an excited state , there is a  likelihood of spontaneous electrical activity.This can happen in nerve cells, cardiac cells , GI tract,  or virtually in  any cell  which has a porous cell membrane and ionic fluxes across it .

  • Each cell membrane has a resting membrane potential . It  varies between -60 to – 90mv in most cells. When this potential increases there a propensity for  arrhythmias in heart  and convulsions in the brain , peristalsis in intestines and so on .
  • Drugs  like local anesthetic lignociane acts by blocking the  Na+ channels and there by neural activation .Similarly magesium  acts on these channels to reduce the excitability of these cells.
  • We know,  the sharp ascending stroke of cellular  action potential is mediated by Na + .Blockage of this channel blunts the action potential voltage and thus  the  early and late after depolarisation is prevented
  • Magnesium sulphate’s anticonvulsant action is directly  attributable  to this membrane stabilising action

Thus , membrane stabilising action  can be termed as “membrane sedating”  action

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