Defibrillator

[Draco]

I want to know if I got this correct.
A defibrillator stops the heart when is in fibrillation but it cannot be used to restart the heart if the heart was to stop, right?
I need to clear this up as it is causing arguments. I studied this at AS Level and I think that my teacher said the statement above but my parents, who haven't studied biology, believe hospital dramas like Casualty.

[MichaelXY]

What little I know, is that when the heartbeat gets out of sync, or in other words, an erratic heartbeat or fibrillation. The defib is like a reset pulse for the hearts internal pacemaker. I don't think it actually stops the heart, rather resets the heartbeat.

[Jones]

That's what I said.
And I looked it up on the net and on my Encarta Medical Dictionary and both say it just corrects the heartbeat.
Did you ever talk to your teacher, Draco?

[Draco]

I don't see this teacher until Thursday.
My text book says the following:

If fibrillation begins, a warning sound brings a resuscitation team running. They will attempt to shock the heart out of its fibrillation by passing a strong electric current through the chest wall. This usually stops the heart completely for up to 5 seconds, after which it often begins to beat in a controlled way.

That come from Biology 1, chapter 9, page 126.

[Jones]

Well, I don't know... But it just doesn't seem right to me.

[Draco]

Well the text book is written by the exam board that my school uses so what I learn from that will be on the exam.

[Jones]

So, then, regardless of what we say and regardless of any conclusions we might draw from this conversation, you still have to pretend like what the book said is true so that you can pass the test..?
Thats crap.

[Draco]

Tell me about it. Everything I lernt could be proved wrong but I still have to learn it because that is what is written in the exams by the exam board.

[Jones]

*gags* the education systems in almost every country in the world suck.

[Draco]

Well, I've asked my teacher and she said that the defibrillator doesn't restart the heart it only stops it.
She did however say that there may be a different machine that is used to restart the heart but it isn't the defibrillator.

[Jones]

Hm.

[canalon]

A quick look at wikipedia will show that in short the defibrillator stops the heart to allow a synchronized start by the normal regulation mechanisms when the cells are not synchronized any more. So it does not restart the heart, the body is doing that, but it provides condition for the heart to be restarted correctly.

http://en.wikipedia.org/wiki/Defibrillator