# Cardiac Quiz



## Code 3 (Oct 28, 2008)

It's no secret that cirriculums for EMT-B drastically vary from program to program. However, it's interesting to see what some of these differences may be. Try your best to answer the following question. Please do not use the internet or any other forms of research in order to find the answer. *You can, however, use your textbook if the information is provided and it was discussed in class.* The object is to see if this information was given to you during lecture. Please do not hestitate to post vague answers if that is all you know. Good luck!

What are the primary functions of the Sinoatrial Node (SA Node) and Atrioventricular Node (AV Node)?

Extra credit points for those of you that can identify the roles of the Bundle of His and Purkinje Fibers.


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## tydek07 (Oct 28, 2008)

Hi,

I will not answer this, as I am a medic... and well, we learn this stuff inside and out.

I will however tell you that I would not have been able to answer this question before I went to medic school! I would have had no clue haha

This information was *not* covered in my EMT-Basic class at all.

Take Care,


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## Sapphyre (Oct 28, 2008)

Sticking my neck out here, because, well, this was discussed in class, but, for some reason I doubt it was properly discussed.

The SA and AV nodes are, essentially, the heart's internal pacemaker.  The electrical signal telling the heart to contract originates at the SA node.  The AV node helps to regulate the rate.

Bundle of His I've never heard of.  Purkinje Fibers, um, are those the ones that control the valves?


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## rhan101277 (Oct 28, 2008)

We learned this in class, I will give it a shot.  The SA node is the hearts pacemaker, the electrical impulse starts here.  Then it moves onto to the AV node, where just after that point there is some sort of resistance which slows down the signal before it moves onto the bundle of his, giving time for the ventricles to fill.  Then it moves down the septum and across all the purkunji fibers causing the ventricles to contract.  We also learned that in some cases where the SA node cells malfunction that the heart can be paced by the AV node, which results individuals having heart rates of 60bpm rested.

I hope I am not way off base, but our class is extremely stringent so I hope I got it right. This material was covering in class in detail.


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## micsaver (Oct 28, 2008)

What are the primary functions of the Sinoatrial Node (SA Node) and Atrioventricular Node (AV Node)?
    I remember them talking about it briefly in class and then I did some research on my own to learn more. This was a little while ago. I think the SA Node starts the beat rhythm and is the fastest. It sends the signal to the AV node which slows the conduction / beat speed.

Extra credit points for those of you that can identify the roles of the Bundle of His and Purkinje Fibers. The BofH and PF are along the the center and bottom of the Ventricles. The AV node sends the signal to the BofH and PF causing the ventricles to contract.


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## jochi1543 (Oct 28, 2008)

Urgh, without using the book all I can say is that they are pacemakers. SA node is capable of generating the fastest beat, I believe it can make the heart go above 60 bpm? If SA is damaged, AV is able to maintain the heartbeat at a slower rate, I'm tempted to say something like 40-60 bpm. Purkinje fibers are the last resort and they maintain a very slow HR when SA and AV nodes both fail (I think <20? Or 20-40 bpm?). I think they also serve to conduct impulses from the nodes to the heart muscle.

I have no recollection of the function of bundle of His whatsoever, although I definitely studied it in my A&P class before.:wacko:


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## Noctis Lucis Caelum (Oct 28, 2008)

SA Node = Pacemaker, electrical impulse starts and travels to the
AV Node = Regulator, tells SA to slow down if its too fast

I have no idea about the bundle of his and that fibers

Notes are in my backpack, 2 lazy to take'em out but thats whats on my mind right now


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## AnthonyM83 (Oct 29, 2008)

Doubt most people in my class (probably including me) could answer that two months after the course...possibly not even during the course. I'm sure it was briefly covered.

Of course, one should continue their education on their own after EMT class....


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## seanm028 (Oct 29, 2008)

I know that the sinoatrial node is the primary pacemaker for the heart, and that the atrioventricular node takes over if the SA node's rate drops below a certain level.

I believe that the Bundle of His and the Purkinje Fibers are conduction pathways, but I can't tell you their functions besides that.

I learned all this from a book someone gave me called "Basic Arrhythmias".  I don't believe we discussed it in EMT-B class, but I could have just forgotten exactly where I learned it first.  I think we might have gone over the fact that the SA node is the pacemaker.


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## PapaBear434 (Oct 29, 2008)

Code 3 said:


> What are the primary functions of the Sinoatrial Node (SA Node) and Atrioventricular Node (AV Node)?
> 
> Extra credit points for those of you that can identify the roles of the Bundle of His and Purkinje Fibers.



Yeah, I didn't even hear of any of this stuff until my ALS classes.  I just completed EMT-B as of March, so it's not like I went through it a long while ago.  They just don't teach this.

Pretty much what I learned, some of which you've probably seen on those joke lists before:

*If it's bleeding, push on it until it stops.

If it's warm, wet, sticky, and not yours, don't touch it without a glove.

Oxygen.  You can't go wrong with Oxygen.  Lot's and lots of oxygen.  O2 is good, blue is bad.

Air goes in and out,blood goes round and round, any variation on this is a bad thing and should be corrected ASAP. 

The address is never clearly marked.*

The end.  Asking about nodes of the heart is a bit out of the scope of practice.  The only thing we have to worry about regarding the heart is what the little man in the AED tells us in that oh-so-polite but insistent voice.


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## JPINFV (Oct 29, 2008)

PapaBear434 said:


> The end.  Asking about nodes of the heart is a bit out of the scope of practice.  The only thing we have to worry about regarding the heart is what the little man in the AED tells us in that oh-so-polite but insistent voice.



Education is never out a level's scope of practice.


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## EMERG2011 (Oct 29, 2008)

Code 3 said:


> What are the primary functions of the Sinoatrial Node (SA Node) and Atrioventricular Node (AV Node)?
> 
> Extra credit points for those of you that can identify the roles of the Bundle of His and Purkinje Fibers.



SA Node - Primary pacemaker of the heart. Located at the apex of the right atrium. Normally discharges action potentials at a rate of 100/minute, causing the heart to beat. 

AV Node - Located  between atria and the ventricles of the heart, at the origin of the bundle of his. The AV node normally works as a capacitor for the action potential released by the SA node, delaying the transmission of the impulse to the ventricles so that the atria have sufficient time to discharge. In abnormal function, the AV node can act as the primary pacemaker of the heart, and discharges at a rate of 80( think thats right...) beats per minute.

His and Purkinje Fibers - electroconductive fibers of the heart (think: wiring). Transmit the impulse from the SA and AV nodes to the muscle tissues of the heart.

And no - I didnt have to look this up!


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## stephenrb81 (Oct 29, 2008)

JPINFV said:


> Education is never out a level's scope of practice.



Agreed

As an EMT, I was constantly bugging medics "What is that drug" "How does it work" "What does that bump on the monitor mean".

Most were happy to teach, I did work with one that always replied "It's beyond your scope of practice, don't worry about it" but he was a <Insert male genitalia here>

My eagerness to learn before entering a paramedic program helped me fly through pharmacology and cardiac A&P 

Again to quote JPINFV:  Education is *never* out of a level's scope of practice


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## PapaBear434 (Oct 29, 2008)

JPINFV said:


> Education is never out a level's scope of practice.



You misunderstand.  I am currently in my ALS classes, so I am furthering my education.  But the actual training that goes into EMT-B doesn't cover this stuff.


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## stephenrb81 (Oct 29, 2008)

PapaBear434 said:


> You misunderstand.  I am currently in my ALS classes, so I am furthering my education.  But the actual training that goes into EMT-B doesn't cover this stuff.



True, in most cases it isn't but some instructors do add a little advanced A&P to facility understanding.  My basic course actually did cover a little of this so that we had a little more understanding of Vfib/Vtach and how an AED worked.  Granted it wasn't required but it was nicer than simply saying "This shocks the heart to stop it and we hope like hell it starts again"

Now I didn't have a clue about automaticity and such until Medic school


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## mycrofft (Oct 29, 2008)

*SA: ignition coil. AV: distributor. Sort of.*

OK, check these out:

"WPW syndrome"
"Pre-cordial thump"

(No ,the latter is not what you do to someone before they drink a liqeur to make them choke).-_-


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## AbsoluteZzZero (Oct 29, 2008)

The SA node is where the electrical signal first starts. The signal travels from the SA node across the atria and then travels down the middle of the heart(cant remember the correct name for that) and stimulates the AV node where the signal is "regrouped" and sent across the ventricles.

I just typed that from what I remember from class. Didn't read any of these posts or look in my text. But yes, it was definitely explained before we went into "Cardiac Emergencies". Also, just to throw this out, I just graduated from a 3 week intensive course. It was definitely intensive, but super thorough as well!


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## VentMedic (Oct 29, 2008)

AbsoluteZzZero said:


> just graduated from a 3 week intensive course. It was definitely intensive, but super thorough as well!


 
Some of those words don't go together.

Oh wait, you're from Florida. 

Okay, me bad. 

Back to the subject of the thread.


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## JPINFV (Oct 29, 2008)

Since it's quiz time, here's one.

The sympathetic nervous system causes three changes in the heart whereas the parasympathetic only causes two changes in the heart. The two effects of the parasympathetic innervation are directly opposite of the sympathetic nervous system. Which effect of the sympathetic nervous system *is not* counteracted by the parasympathetic nervous system?


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## Sasha (Oct 29, 2008)

mycrofft said:


> OK, check these out:
> 
> "WPW syndrome"
> "Pre-cordial thump"
> ...



Pre-cordial thump is when you witness a pt go into v-fib/v-tach but dont have a defibrillator immediately handy but its on its way ( think AH! Get the defibrillator/crash cart out of room 6!! ) and it delivers around 5J, I think, of energy. Its not part of protocol anymore, is it?

WPW, Wolff Parkinson White syndrome is a rare, congenital heart problem. Isnt that where there are extra accessory pathways between the atria and the ventricles? Arent they usually tachy? Verapamil and digoxin are contraindicated for WPW.


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## stephenrb81 (Oct 29, 2008)

Sasha said:


> Pre-cordial thump is when you witness a pt go into v-fib/v-tach but dont have a defibrillator immediately handy but its on its way ( think AH! Get the defibrillator/crash cart out of room 6!! ) and it delivers around 5J, I think, of energy. Its not part of protocol anymore, is it?



Saw a medic nearly get his posterior whooped by a HUGE burly husband when the medic ran from the nurses station to the patient's bed and thumped her.

I can only imagine: speaking to my wife, she suddenly says her chest is tightening and then a blur as a guy runs in and basically punches her in the chest for no apparent reason lol


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## AbsoluteZzZero (Oct 30, 2008)

VentMedic said:


> Some of those words don't go together.
> 
> Oh wait, you're from Florida.
> 
> ...



Eh, its the same amount of hours put into a full time class.. Rather than going to class 2 nights a week while working full time and then studying when I could fit it in, I went to class for 8 hours a day and then studied for 2-3 hours every night. For me, I think it was a better learning environment.. But to each his own..


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## mycrofft (Oct 30, 2008)

*I believe the precordial thump is "out".*

Hard to "thump on T", likely to cause mechanical damage to lots of things without much proveable benefit...except if your protocols call for it, then it's the best thing since sliced Lifepak.

PS: Good article on WPW. 

http://en.wikipedia.org/wiki/Wolff-P...White_syndrome


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## mycrofft (Oct 30, 2008)

*OOps duplicate post*

10characters


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## Ridryder911 (Oct 30, 2008)

Sasha said:


> Pre-cordial thump is when you witness a pt go into v-fib/v-tach but dont have a defibrillator immediately handy but its on its way ( think AH! Get the defibrillator/crash cart out of room 6!! ) and it delivers around 5J, I think, of energy. Its not part of protocol anymore, is it?




Actually it about 7-14 joules. Yes, it is still part of AHA emergency treatment procedure and *YES * it *works!* 

The patient needs to be already on a monitor, and it is performed quickly and effectively. As Sasha describes it used until a defibrillator is on hand. For example a ICU or bedside monitor that does not have a defibrillator attached. Producing the "stimulation" during the *vulnerable period *of the muscle activity is what makes it work. 

R/r 911


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## Sasha (Oct 30, 2008)

Ridryder911 said:


> Actually it about 7-14 joules. Yes, it is still part of AHA emergency treatment procedure and *YES * it *works!*
> 
> The patient needs to be already on a monitor, and it is performed quickly and effectively. As Sasha describes it used until a defibrillator is on hand. For example a ICU or bedside monitor that does not have a defibrillator attached. Producing the "stimulation" during the *vulnerable period *of the muscle activity is what makes it work.
> 
> R/r 911



I was close!! 

Ive heard its falling out of favor because people do it incorrectly and cause further harm.


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## Ridryder911 (Oct 30, 2008)

Sasha said:


> I was close!!
> 
> Ive heard its falling out of favor because people do it incorrectly and cause further harm.




Very true, as well as most units and med surg floors has "crash carts" available with AED's and Defib/monitors so "Edison Medicine" can be provided. 

R/r 911


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## KEVD18 (Oct 30, 2008)

mycrofft said:


> 10characters



just a though im throwing out there for you:

if you didnt post the first sentence of every post you make as the subject(which is an optional field), that wouldnt have been necessary.

again, just a thought....


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## SpudCrushr (Nov 26, 2008)

Uh, say what? I don't remember learning about them


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## Ridryder911 (Nov 26, 2008)

SpudCrushr said:


> Uh, say what? I don't remember learning about them



Basics are not taught such as it is an Advanced Procedure. 

R/r 911


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## MattCA (Nov 26, 2008)

I just remember it being the hearts pacemaker


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## ResTech (Nov 27, 2008)

The SA and AV nodes are specialized tissue that have pacemaking responsibilities within the heart. The SA node (located within the right atrium), is the hearts dominant pacemaker with an intrinsic rate of 60-100. I think the rate is stated to be slightly higher however with vagal influence the SA node produces the normal heart rate of 60-100min. 

The AV node serves two primary functions: 1) a conduction delay. 2) a fail safe / secondary pacemaker. In addressing #1, in order for the mechanical function of the heart to work properly, a delay of the SA node impulse must take place at the AV node in order for blood to be ejected from the atrium into the ventricles. If the SA node fails, then the AV node will kick in as a fail safe and pace the heart at its intrinsic rate of 40-60min.


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## whiteoleander28 (Nov 27, 2008)

Since the question's already been thoroughly answered multiple times, I'll just mention that yes, we definitely did go over this in lecture - EMT B


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