[HSF] Inotropes, ventricular fibrillation and myocardial protection

[Ben Bidstrup]

I beg respectfully to differ. The lidocaine (a fast Na channel 
blocker) is all but gone after a short while in the cardioplegia 
scenario. Getting a suitable level back into the circulation and thus 
the heart at release of the clamp is what is needed.

Perhaps a randomised study is in the offing.

http://circ.ahajournals.org/cgi/content/abstract/79/5/1106

This reference relates to defib energy levels but i think you will 
see where I am coming from.

At James Cook, I was involved in the development of a non 
depolarising cardioplegia solution, which is slowly working its way 
up the development path. The main components are lidocaine and 
adenosine.




>Ben,
>I use Amiadorone in the pump for all emazes (and postop) and 
>Amiadorone in the pump for all aortic valves. Since the St Thomas 
>Cardioplegia (which we mix in blood) already has procaine adding 
>Lignocaine would be redundant.(Incidentally Amiadorone is very cheap 
>in India !!)
>Prasanna
>Ben Bidstrup wrote:
>>Why the amiodarone. Surely with some perfusion, the electrolyte 
>>imbalances within the myocardium would correct and SR ensue. If 
>>anything use lidocaine. Less toxic and cheaper, not a negative 
>>inotrope. It is what Yacoub taught me many years ago, and I have 
>>used it to good effect (infrequently I might add).
>>
>>>Tohru,
>>>   I did an AVR on an 87 yo man as a 2nd case just a couple of 
>>>hours  ago. Again, no LV vent, only a sump.  While closing the 
>>>aortotomy, I  began the
>>>continuous warm retrograde blood.  The heart began fibrillating 
>>>after a couple of
>>>minutes.  I gave amio and then cardioverted.  The  heart had a 
>>>slow junctional
>>>rhythm until the clamp was released.  A sinus  rhythm developed shortly
>>>afterwards.  He came off with no inotropes.   It's much easier on 
>>>the heart and
>>>your nerves to cardiovert a clamped, flaccid  heart rather than 
>>>trying to do it
>>>after the clamp has been released.
>>>   I look forward to your visit at the STS.  As I said before,  I'll try to
>>>have a couple of interesting cases for you and other interested 
>>>members of HSF
>>>to watch and criticize to your heart's content.
>>>
>>>Hal
>>>
>>>
>>>
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>>
>
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-- 


Two things are infinite; the universe and human stupidity; and I am 
not sure about the universe.
Albert Einstein

The greatest obstacle to discovery is not ignorance --- it is the 
illusion of knowledge.
Daniel J Boorstin

Ben Bidstrup FRACS FRCSEd FEBCTS
Consultant Cardiothoracic Surgeon