# EKG strip confusion



## Chief Complaint (Apr 4, 2011)

Im working on a homework assignment for my ACLS course and im a little confused by the following scenario.  The assignment calls for us to look at a strip, identify it, and then devise a treatment plan in accordance with the ACLS guidelines.

Scenario is as follows:

"A 27 year old male is involved in an MVA.  The patient is found lying outside his vehicle, unconscious, unresponsive, apneic, and pulseless.  Rapid trauma assessment reveals the following: trachea deviated to the left, jugular veins distended, absent lung sounds on the right."

Here is the strip:








How would it be possible for this rhythm to be present in an apneic, pulseless patient?  

Is this a trick question?  Did my teacher accidentally attach the wrong strip?  Or am i missing something here?  Any input is greatly appreciated.


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## Shishkabob (Apr 4, 2011)

Trust me, not even close to a trick question and very easy to interpret, diagnose the possible cause and we can even treat it.  


Hmm... you mean there's electrical activity WITHOUT a pulse?  I wonder what that translates to... if only there was a 3 letter word....


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## Chief Complaint (Apr 4, 2011)

I know i know!  PEA was the first thing that came to my mind, ive just never heard of it looking anything like this?  Is that possible?

Every example of PEA that ive seen in the classroom so far has had some sort of bizarre morphology.


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## Shishkabob (Apr 4, 2011)

If it's a rhythm otherwise capable of causing a perfusing beat (afib/aflutter/NSR/Sinus tach/sinus brady etc etc) but there is no beat, it's PEA.


So yes, normal sinus can be PEA.


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## Chief Complaint (Apr 4, 2011)

I didnt know that, thanks for the help.  

Wow do i feel like a dummy for not knowing that NSR could be pulseless.


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## Shishkabob (Apr 4, 2011)

You know Vtach can have a pulse, too, right?


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## JPINFV (Apr 4, 2011)

I personally like the old term... electromechanical disjunction (EMD).


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## Chief Complaint (Apr 4, 2011)

Linuss said:


> You know Vtach can have a pulse, too, right?



I deserve whatever you wish to throw at me.


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## jjesusfreak01 (Apr 4, 2011)

JPINFV said:


> I personally like the old term... electromechanical disjunction (EMD).



The weird thing is just that I wouldn't expect for the heart to depolarize correctly throughout, but have no contractile response to speak of. Why is the heart stopped. Obviously the electrical system is perfusing correctly, but the mechanical system is not.


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## Shishkabob (Apr 4, 2011)

JPINFV said:


> I personally like the old term... electromechanical disjunction (EMD).




I like "electromechanical disassociation" more 




jjesusfreak01 said:


> The weird thing is just that I wouldn't expect for the heart to depolarize correctly throughout, but have no contractile response to speak of. Why is the heart stopped. Obviously the electrical system is perfusing correctly, but the mechanical system is not.



Obstructive shock caused by a tension pneumothorax.


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## JPINFV (Apr 4, 2011)

Linuss said:


> I like "electromechanical disassociation" more



Yea.. yea... we'll see when I take ACLS next month...


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## johnmedic (Apr 8, 2011)

jjesusfreak01 said:


> The weird thing is just that I wouldn't expect for the heart to depolarize correctly throughout, but have no contractile response to speak of. Why is the heart stopped. Obviously the electrical system is perfusing correctly, but the mechanical system is not.



Now that you know that PEA can be normal sinus, Pericardial Tamponade would be the most likely cause, or maybe a massive Hemothorax could theoretically put enough pressure on the heart? (Don't quote me on the second one!) Or just massive hemorrhage would drop the CO enough to lose pulses.. you should be able to build a pretty good list for the differential diagnosis, goodluck.

& @Linus (since I can't multiquote) Your PEA statement's true except for Pulseless VT, it's not under the PEA algorythm but the rhythm is capable of creating a perfusing beat. No disrespect, I know you know, just saying.


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## usalsfyre (Apr 8, 2011)

Linuss said:


> Obstructive shock caused by a tension pneumothorax.


Linuss diagnosed it for you, what's the treatment?

Bonus question, is tension pneumo an inflow or outflow obstruction?


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## usalsfyre (Apr 8, 2011)

johnmedic said:


> & @Linus (since I can't multiquote) Your PEA statement's true except for Pulseless VT, it's not under the PEA algorythm but the rhythm is capable of creating a perfusing beat. No disrespect, I know you know, just saying.


It's still technically PEA, it just lives in it's own algorithm . Honestly the whole idea of a PEA "algorithm" is pretty idiotic. Unless you can immediately identify and correct the underlying cause, you might as well not even bother.


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## firetender (Apr 8, 2011)

*Here's what I wonder about...*



Chief Complaint said:


> devise a treatment plan
> 
> 27 year old male
> MVA.
> found lying outside his vehicle, unconscious, unresponsive, apneic, and pulseless.


 
That's the way he was found, but by WHO? Because...




> Rapid trauma assessment:
> trachea deviated to the left,
> jugular veins distended,
> *absent lung sounds on the right.*



Jugular veins distended by what? Non-circulating blood?
To deduce there are no lung sounds on the Right, there would have to be lung sounds on the Left.

Sounds like evidence that by the time the medics began their "rapid trauma assessment" the patient started his own vitals up again or the reporter didn't know what he/she was talking about.



> How would it be possible for this rhythm to be present in an apneic, pulseless patient?



It couldn't because he wasn't. I would like to see the scenario cut and pasted here EXACTLY as you were given it. I suspect something got lost in the translation. If not, it's one of the most misleading scenarios I ever read.


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## abckidsmom (Apr 8, 2011)

firetender said:


> That's the way he was found, but by WHO? Because...
> 
> 
> 
> ...



Dead people with pneumos who are lying flat can and do have JVD all the time.  Jugular veins distended by blood in the vasculature that can't enter the thoracic cavity.

And if he had lung sounds on the right but not the left, I'm going to guess someone's ventilating the patient and he has a Right sided tension pneumo.



> Sounds like evidence that by the time the medics began their "rapid trauma assessment" the patient started his own vitals up again or the reporter didn't know what he/she was talking about.
> 
> 
> 
> It couldn't because he wasn't. I would like to see the scenario cut and pasted here EXACTLY as you were given it. I suspect something got lost in the translation. If not, it's one of the most misleading scenarios I ever read.



Everything in the scenario seems perfectly plausible to me.


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## Epi-do (Apr 8, 2011)

usalsfyre said:


> It's still technically PEA, it just lives in it's own algorithm . Honestly the whole idea of a PEA "algorithm" is pretty idiotic. Unless you can immediately identify and correct the underlying cause, you might as well not even bother.



On a somewhat unrelated side note, I couldn't tell you how many times I have heard our medical director state, "PEA is not a rhythm.  It is a descriptor of the rhythm.  You still have to identify the rhythm!"


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## Aidey (Apr 9, 2011)

Ooooh that is a pet peeve of mine too. Same thing with BBB. Ok, great it is a BBB what is the underlying rhythm?


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## systemet (Apr 9, 2011)

A couple of quick points:-

(1) The activity we see on the ECG is due to depolarisation of the myocardium.  We often make statements like "the SA node causes the P wave" -- this is true only in as far as the SA node initiates depolarisation of the atrial myocardium, the signal we see on the ECG as the P wave is the aggregate of the electrical signal produces by millions of cardiomyocytes in the atrium.  If the signal from the SA node is blocked (e.g. SA exit block - http://en.ecgpedia.org/wiki/Sino-atrial_exit_block), the P wave is absent.  PEA is not due to a failure of the cardiomyoctes to depolarise.  If they did not depolarise we would see asystole.

(2) In PEA, the cardiomyocytes are depolarising, but this is not translating into enough of a contraction to produce a carotid pulse.  There may be a measurable, but low, central pressure (pseudo-EMD), and wall movement observed on echo -- or there may be no wall motion.  This can be due to mechanical obstruction, e.g. tension pneumothorax, pericardial tamponade.  It may result from hypovolemia -- i.e. there is no/little blood entering the heart, so insufficient preload = negligble CO, low arterial pressure, and no carotid pulse.  It may occur in the absence of mechanical obstruction, in situations where the cardiomyocytes are depolarising, but the contracticle apparatus is unresponsive, e.g. acidosis, hypothermia, etc.

(3) PEA does not result from a selective perfusion of "electrical systems" of the heart, while muscular systems are spared.  For instance, the AV node is typically supplied by a branch of the RCA, whereas the left anterior fasicular branch is typically supplied by the LAD.  The SA node may be supplied by the left or the right circulation; the posterior fascile of the LBBB typically has dual blood supply.  All this is subject to some variation in the population, and regions of the electrical conduction system often have multiple collaterals.  To selectively isolate the electrical conduction system, while preserving the myocardium would require multiple thrombi or emboli located in extremely small distal vessels in specific places.  It's functionally impossible.


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