On 15-6-2009 14:02, Stephen wrote:

> electrical impulses to the heart are interrupted and fibrillation occurs. IIRC
> there are parts of the heart that receive the electrical impulses from the
> brain then transmit secondary impulses to the muscle tissue to contract and
> relax in an organised way. 

No the heart is autonomous, will even beat outside the body for some 
time (hours) if oxygenated. It's frequency can be modulated by stuff in 
the blood and by nerve tissue that is close to the sinus node when they 
release special molecules.

> The electrical shock interrupts this process and you
> get a disorganised high frequency oscillation in different parts of the heart. 

No, but what happens is much more complicated (i.e. you need a 
complicated model to describe it and even then you see it happening 
without getting much more understanding, but it works).
Standard procedure to induce VF in an open chest heart: hold a 9V 
battery against it. And, no, I don't know how it actually works, but it 
does.

> A defibrillator is used to stop this effectively stopping the heart and the
> natural sinus rhythm can be resumed. Before defibrillators became commonplace
> the manual method was to strike the victims chest above the heart with a
> controlled blow using the pinkie side of your fist. This was supposed to have


I does work sometimes. http://en.wikipedia.org/wiki/Precordial_thump Do 
not apply to people that are not in VF: 
http://en.wikipedia.org/wiki/Commotio_cordis

Post a reply to this message

andrel wrote:

> No the heart is autonomous, will even beat outside the body for some 
> time (hours) if oxygenated.

Does anybody else find it slightly disturbing that andrel knows such things?

I mean, I know there's a good reason, but even so... kinda grusome.

Post a reply to this message

andrel <a_l### [at] hotmailcom> wrote:
> On 15-6-2009 14:02, Stephen wrote:

> > electrical impulses to the heart are interrupted and fibrillation occurs. IIRC
> > there are parts of the heart that receive the electrical impulses from the
> > brain then transmit secondary impulses to the muscle tissue to contract and
> > relax in an organised way.
>
> No the heart is autonomous, will even beat outside the body for some
> time (hours) if oxygenated. It's frequency can be modulated by stuff in
> the blood and by nerve tissue that is close to the sinus node when they
> release special molecules.
>

I thought that you might respond :)



> > The electrical shock interrupts this process and you
> > get a disorganised high frequency oscillation in different parts of the heart.
>
> No, but what happens is much more complicated (i.e. you need a
> complicated model to describe it and even then you see it happening
> without getting much more understanding, but it works).
> Standard procedure to induce VF in an open chest heart: hold a 9V
> battery against it. And, no, I don't know how it actually works, but it
> does.
>

You are the expert I'm only a first aider


> > A defibrillator is used to stop this effectively stopping the heart and the
> > natural sinus rhythm can be resumed. Before defibrillators became commonplace
> > the manual method was to strike the victims chest above the heart with a
> > controlled blow using the pinkie side of your fist. This was supposed to have

>
> I does work sometimes. http://en.wikipedia.org/wiki/Precordial_thump Do
> not apply to people that are not in VF:

Unless you want to kill them ;)

Stephen

Post a reply to this message

On 15-6-2009 17:30, Invisible wrote:
> andrel wrote:
> 
>> No the heart is autonomous, will even beat outside the body for some 
>> time (hours) if oxygenated.
> 
> Does anybody else find it slightly disturbing that andrel knows such 
> things?
> 
> I mean, I know there's a good reason, but even so... kinda grusome.

As you may be aware, it is my job. It comes with being in a experimental 
cardiology lab. BTW a beating heart is absolutely not gruesome, I would 
rather say beautiful. I'd be happy to show you if you happen to be in 
Amsterdam some time and an experiment is running. ;)

Post a reply to this message

Invisible wrote:
> Does anybody else find it slightly disturbing that andrel knows such 
> things?

You don't watch enough TV.

-- 
   Darren New, San Diego CA, USA (PST)
   Insanity is a small city on the western
   border of the State of Mind.

Post a reply to this message

>>> No the heart is autonomous, will even beat outside the body for some 
>>> time (hours) if oxygenated.
>>
>> Does anybody else find it slightly disturbing that andrel knows such 
>> things?
>>
>> I mean, I know there's a good reason, but even so... kinda grusome.
> 
> As you may be aware, it is my job. It comes with being in a experimental 
> cardiology lab.

Indeed. But still... kinda freaky.

> BTW a beating heart is absolutely not gruesome, I would 
> rather say beautiful. I'd be happy to show you if you happen to be in 
> Amsterdam some time and an experiment is running. ;)

I once saw an operation on TV. They cut open a guy's chest, ripped his 
ripcage apart, and inside was his heart. I swear, it honestly looked 
like it was trying to CLIMB THE HELL OUT OF HIS BODY AND RUN AWAY!! O_O

*shivers*

Post a reply to this message

>> Does anybody else find it slightly disturbing that andrel knows such 
>> things?
> 
> You don't watch enough TV.

I always thought I watch far too much TV. :-P

Post a reply to this message

On 15-6-2009 17:33, Stephen wrote:
> andrel <a_l### [at] hotmailcom> wrote:
>> On 15-6-2009 14:02, Stephen wrote:

>>> electrical impulses to the heart are interrupted and fibrillation occurs. IIRC
>>> there are parts of the heart that receive the electrical impulses from the
>>> brain then transmit secondary impulses to the muscle tissue to contract and
>>> relax in an organised way.
>> No the heart is autonomous, will even beat outside the body for some
>> time (hours) if oxygenated. It's frequency can be modulated by stuff in
>> the blood and by nerve tissue that is close to the sinus node when they
>> release special molecules.
>>
> 
> I thought that you might respond :)


Thanks for assuming that there are only kids in this newsgroup. ;)

I disagree, a lie for children is when you explain something highly 
simplified and/or deliberately wrong because the actual facts are to 
difficult. Suggesting that the heart is driven by the nervous system is 
simply wrong and what actually happens is just as easy to understand. 
Involving the brain will in a bright child immediately lead to questions 
what happens when you sleep or are unconscious. The child might even 
fear to go to sleep. It does not explain coma or how a paralysed person 
can live. So, please, if you have children, tell them a simplification 
of the truth, but never that your brain dictates when the heart has to 
beat.

Post a reply to this message

On 15-6-2009 17:56, Invisible wrote:
>>>> No the heart is autonomous, will even beat outside the body for some 
>>>> time (hours) if oxygenated.
>>>
>>> Does anybody else find it slightly disturbing that andrel knows such 
>>> things?
>>>
>>> I mean, I know there's a good reason, but even so... kinda grusome.
>>
>> As you may be aware, it is my job. It comes with being in a 
>> experimental cardiology lab.
> 
> Indeed. But still... kinda freaky.
> 
>> BTW a beating heart is absolutely not gruesome, I would rather say 
>> beautiful. I'd be happy to show you if you happen to be in Amsterdam 
>> some time and an experiment is running. ;)
> 
> I once saw an operation on TV. They cut open a guy's chest, ripped his 
> ripcage apart, and inside was his heart. I swear, it honestly looked 
> like it was trying to CLIMB THE HELL OUT OF HIS BODY AND RUN AWAY!! O_O
> 
> *shivers*

Was that a dramatazation or an actual procedure?

Post a reply to this message

>>> BTW a beating heart is absolutely not gruesome, I would rather say 
>>> beautiful. I'd be happy to show you if you happen to be in Amsterdam 
>>> some time and an experiment is running. ;)
>>
>> I once saw an operation on TV. They cut open a guy's chest, ripped his 
>> ripcage apart, and inside was his heart. I swear, it honestly looked 
>> like it was trying to CLIMB THE HELL OUT OF HIS BODY AND RUN AWAY!! O_O
>>
>> *shivers*
> 
> Was that a dramatazation or an actual procedure?

It was meant to be the real thing. Apparently there was something or 
other wrong with this guy's heart, so they were going to rip it out and 
stick a new one in. (I wasn't really paying attention.) The new heart 
looked rather limp and pale. But the still-beating one looked evil! (And 
several sizes too big for the chest cavity, BTW...)

-- 
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*

Post a reply to this message