[HSF] Inotropes, ventricular fibrillation and myocardial protection

Wed Aug 1 22:34:43 EDT 2007

The choice of adding a particular drug has been based on experimental 
work and not just picked out of the blue. Yes people do cases with 
crystalloid and others with blood and so on and so forth but with each 
method there is some modifications which may give the good result in 
that particular persons hands if he recognizes the limiting factor in 
his /her technique.The sequential changes and their relative merits and 
demerits have originally been referred  to by Mark Baimbridge's team and 
Buckberg and these have not been just pulled out of the hat. Adding 
adenosine, Esmolol and NTG, Insulin etc were all done to address a 
specific problem in the cardioplegic method that was used by me. 
Resolution of that problem was noted with some objective evidence of 
preservation be it myocardial function, CS Lactates and 5 min CS oxygen 
levels ,Inotropic usage and negation of a risk factor. I would not 
consider that voodoo !!
I still strongly believe that clamp release with fibrillation indicates 
that there has been some deficiency in protection. Whether this leads to 
a poor outcome would be based on the hearts compensatory mechanisms. Any 
method that makes the heart compensate less is better.
If we say one shock is inconsequential then what would you say if we 
then need multiple shocks to defibrillate the heart ?
Prasanna
Ani Anyanwu wrote:
> Prasanna
>  
> What you do now is no less voodoo that what you graduated from; indeed your current cardioplegia recipe is very much a 'homemade cocktail'. We have to be careful in ascribing benefits to things we do without being able to demonstrate such benefits scientifically.Many never add drugs like adenosine and esmolol, as you might do, to cardioplegia and have good results. I recall recently, one of our senior members (maybe Dr Tom Martin?) said he still uses crystalloid cardioplegia and yet has fantastic results in very complex cases several of which he has shared on this forum. Indeed the more I quiz people about this 'fibrillation is bad' theory the less I am convinced about it. A day or two ago I learnt from Hal that he sometimes defibrillates with the clamp on and then that later will count as the heart being in SR when you declamp? Tohru induces fibrillation in all patients and has good results. We also learnt that many of us actually don't even know what is in the cardioplegia or hot-shot we use.
>  
> Cardioplegia is indeed still voodoo. There are basic principles which have to be adhered to depending on whether you are cold or warm, arrested or beating; aside from this, most of the rest is voodoo, including, I suspect, the suggestion that transient fibrillation indicates poor protection.
>  
> Ani
>
>
>
>   
>> Date: Wed, 1 Aug 2007 20:15:53 +0530> From: prasannasimha at gmail.com> To: OpenHeart-L at lists.hsforum.com> Subject: Re: [HSF] Inotropes, ventricular fibrillation and myocardial protection> CC: > > Ani,> Having graduated from voodoo homemade cocktails to blood and its > variants, you would easily be able to see that the bad cardioplegia's > did have a higher (more accurately uniform) incidence of fibrillation > which came down with better modifications of cardioplegia's. That does > make us wary and anyway fibrillation is not something by any stretch > normal.Transient defibrillation may appear innocuous but then it has > been shown that such hearts have indeed been improperly preserved (from > works of Buckberg and Kirklin).Remember that sometimes speed etc etc may > compensate but this may become an issue in longer case.> Prasanna> Ani Anyanwu wrote:> > I still do not understand why we are alarmed about transient ventricular fibrillation on reperfusion and why using drugs to suppress it will have any impact on outcome.> > > > Ani> >> >> >> > > >> Date: Wed, 1 Aug 2007 11:51:47 +0530> From: prasannasimha at gmail.com> To: OpenHeart-L at lists.hsforum.com> Subject: Re: [HSF] Inotropes, ventricular fibrillation and myocardial protection> CC: > > I am not saying that the procaine or lignocaine is still acting. What I> meant is that since the fibrillation is occurring with the hotshot delivery> with high local lignocaine changing the drug class may be beneficial.> Prasanna> > On 8/1/07, Ben Bidstrup <benjamin.bidstrup at bigpond.com> wrote:> >> > 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> > >>>> > >>>> > >>>> > >>>************************************** Get a sneak peek of the> > >>>all-new AOL at> > >>>http://discover.aol.com/memed/aolcom30tour> > >>>_______________________________________________> > >>>OpenHeart-L mailing list> > >>>> > >>>Send postings to:> > >>> OpenHeart-L at lists.hsforum.com> > >>>> > >>>To UNSUBSCRIBE, to CHANGE email address, or to view archives:> > >>>http://mmp.cjp.com/mailman/listinfo/openheart-l> > >>>> > >>>All messages transmitted by the OpenHeart-L are subject to the policies> > and> > >>>disclaimers posted at:> > >>>http://www.hsforum.com/listdisclaim> > >>>-----------------------------------------> > >>> > >>> > >> > >_______________________________________________> > >OpenHeart-L mailing list> > >> > >Send postings to:> > >OpenHeart-L at lists.hsforum.com> > >> > >To UNSUBSCRIBE, to CHANGE email address, or to view archives:> > >http://mmp.cjp.com/mailman/listinfo/openheart-l> > >> > >All messages transmitted by the OpenHeart-L are subject to the> > >policies and disclaimers posted at:> > >http://www.hsforum.com/listdisclaim> > >-----------------------------------------> >> >> > --> >> >> > 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> > _______________________________________________> > OpenHeart-L mailing list> >> > Send postings to:> > OpenHeart-L at lists.hsforum.com> >> > To UNSUBSCRIBE, to CHANGE email address, or to view archives:> > http://mmp.cjp.com/mailman/listinfo/openheart-l> >> > All messages transmitted by the OpenHeart-L are subject to the policies> > and> > disclaimers posted at:> > http://www.hsforum.com/listdisclaim> > -----------------------------------------> >> > > > -- > Prasanna Simha M> _______________________________________________> OpenHeart-L mailing list> > Send postings to:> OpenHeart-L at lists.hsforum.com> > To UNSUBSCRIBE, to CHANGE email address, or to view archives:> http://mmp.cjp.com/mailman/listinfo/openheart-l> > All messages transmitted by the OpenHeart-L are subject to the policies and > disclaimers posted at:> http://www.hsforum.com/listdisclaim> -----------------------------------------> >> > > _________________________________________________________________> > 100’s of Music vouchers to be won with MSN Music> > https://www.musicmashup.co.uk/index.html_______________________________________________> > OpenHeart-L mailing list> >> > Send postings to:> > OpenHeart-L at lists.hsforum.com> >> > To UNSUBSCRIBE, to CHANGE email address, or to view archives:> > http://mmp.cjp.com/mailman/listinfo/openheart-l> >> > All messages transmitted by the OpenHeart-L are subject to the policies and > > disclaimers posted at:> > http://www.hsforum.com/listdisclaim> > -----------------------------------------> >> >> > > > _______________________________________________> OpenHeart-L mailing list> > Send postings to:> OpenHeart-L at lists.hsforum.com> > To UNSUBSCRIBE, to CHANGE email address, or to view archives:> http://mmp.cjp.com/mailman/listinfo/openheart-l> > All messages transmitted by the OpenHeart-L are subject to the policies and > disclaimers posted at:> http://www.hsforum.com/listdisclaim> -----------------------------------------
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