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Posts Tagged ‘scd’

Implantable cardiovertor defibrillator(ICD)  is one of the major revolution in cardiology practice  that happened last century. We know , the number one killer of mankind is the ventricular fibrillation induced by acute or chronic CAD.

In the  later half of 20th century we  learnt  that , the only way to prevent a sudden cardiac death is the defibrillating   the  heart as soon as the deadly killer arrhythmia strikes !

Whenever cardiac arrest happens  in  a susceptible population , following  things are possible.

  • Call 911 /108  start CPR .
  • Have  Automatic external defibrillator AED at home
  • ICD implantation -Percutaneous trans-venous approach

And now new mode of defibrillation

Transvenous implantation  becomes  technically complex in many  .Abandoning the procedure  or using subcutaneous pads are necessary in few . Then , this question was asked

Why not the entire ICD implantation be in  subcutaneous plane ?

Yes , it is possible . After all , current can reach the  place where  it is needed ,  irrespective of the site it is delivered. The aim of this technique is to  simplify the ICD implantation  , so that it can be practiced in a wider clinical set up Preliminary  results  of subcutaneous ICD are available and was published  recently in NEJM.

The issues that need to be tackled are

  • Amount of energy required
  • Battery life

http://www.cameronhealth.com/product-info.htm

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To further understand women's heart click on the title

SCD  continues to be  the major mode of  death of  our  population . Millions of men die every year instantly .The commonest mechanism is due to primary ventricular fibrillation following an abrupt closure of coronary artery due to a thrombus.Most die , within few minutes of the event, some  before reaching the hospital , few within the ambulance  and an  unlucky few die on the CCU bed  or cath lab table even after getting the best treatment.

If we analyse the data, there is a  surprising fact !  Men form the bulk of these SCD victims.In our experience , out of 100 cases of consecutive  in hospital primary VF only  6 were females , indicating  an important  biological phenomenon to be studied.The data for out of hospital primary VF is more difficult to get , but the  log records of EMRI and emergency rescue team consistently confirm the male preponderance of primary VF .

How  does the female heart enjoys this relative immunity from primary VF even as the blood supply is acutely compromised ?

The answer  is  not known . If we are able to  decode this , one can replicate the same  model in male .

The QT paradox and incidence of primary VF

QT interval represents a combination of  electrical depolarisation and repolarisation .It is a well established   scientific  fact  that  women have   relatively  prolonged QT interval .This  is determined by evolutionary biology and  inherited characteristics of  potassium channels  during myocardial repolarisation

In simple terms, the female heart  knows how to relax slowly and prolong the electrical relaxation time.(Not mechanical)

It is also a well known  fact ischemia mediated a prolonged  QT interval is a trigger for dangerous ventricular arrhythmia.This ischemia induced QT prolongation is less pronounced in females than males as the baseline QT itself is slightly longer in women.The percentage increment of QT interval during acute ischemia is significantly higher in male .This could be one reason for the preponderance of VF in men

The billion dolor question and a real challenge for the cardiologists is

How to make a heart electrically inert during ongoing ischemia ?

  • Pain is also trigger for primary VF due to high adrenergic tone.Prompt control of chest pain make VF less likely.
  • Lignoacaine a myocardial anesthetic if administered quickly can prevent many of the primary VF.

And now , shall we  think little wildly !

What if , if  we administer lignocaine spray straight over the (or sublingually ) in every patient with  chest pain

as like a sport injury and try calm down the heart electrically !

Also read

1.Lignocaine  the forgotten hero .

2.View this video -Ignorance based cardiology !

Reference

Arrhythmias and sex hormones


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