EKG tracings

[medman88]

I have two questions:

1. How do you tell the difference between ventricular fib and ventricular tachy, i know tachy can lead to fib but to me they look pretty much identical.

2. Does anyone know of a good source to practice tracings?

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[loveoforganic]

I'm not sure if this is 100%, but what I've always used to distinguish the two is that vfib is more irregular and lower amplitude

 

[Phloston]

Ventricular fibrillation doesn't have any discernable rhythm. It's fatal if it's not converted. There are no p-waves. There are no QRS-complexes. There isn't anything. Some sources might say that it's a rhythm with 3-600 beats per minute, but there isn't actually any rhythm.

Ventricular tachycardia is an actual rhythm with rapid QRS complexes. The complexes are almost always narrow. If they're wider, it's SVT or a VT with a BBB.

 

[medman88]

Ventricular fibrillation doesn't have any discernable rhythm. It's fatal if it's not converted. There are no p-waves. There are no QRS-complexes. There isn't anything. Some sources might say that it's a rhythm with 3-600 beats per minute, but there isn't actually any rhythm.

Ventricular tachycardia is an actual rhythm with rapid QRS complexes. The complexes are almost always narrow. If they're wider, it's SVT or a VT with a BBB.

Awesome! thanks!

 

[AndyRSC]

ventricular tachycardia... Complexes are almost always narrow. If they're wider, it's svt or a vt with a bbb.

wt...f?

 

[JackShephard MD]

...

 

[AndyRSC]

Hmm, buried in those walls of text are relevant points.

Anyway, medman, I wouldn't worry too much about it, as the rhythms they'll give you will be clear-cut. The vfib strips you'll get will like like the bottom one:

Random, disorganized quivering. In a word, chaos.

Contrast it with the top, which shows vtach. Definite pattern, consistent width. In a word, order.

You'll sometimes get a ventricular tachycardia that has polymorphic features ("torsades"). To put it simply, the height will alternate, but there will be consistent wave width and an overall order to the rhythm:

And, of course, for this one you'll push magnesium sulfate in addition to other usual tx.

I wouldn't take it beyond FA for Step I (other than being able to determine axis deviation). Just recognize the overall patterns and know the treatment. Worry about guidelines and nuances when you're taking ACLS or as you go into your third year.

Oh, and take everything you read on these forums with a grain of salt.

 

[medman88]

Hmm, buried in those walls of text are relevant points.

Anyway, medman, I wouldn't worry too much about it, as the rhythms they'll give you will be clear-cut. The vfib strips you'll get will like like the bottom one:

Random, disorganized quivering. In a word, chaos.

Contrast it with the top, which shows vtach. Definite pattern, consistent width. In a word, order.

You'll sometimes get a ventricular tachycardia that has polymorphic features ("torsades"). To put it simply, the height will alternate, but there will be consistent wave width and an overall order to the rhythm:

And, of course, for this one you'll push magnesium sulfate in addition to other usual tx.

I wouldn't take it beyond FA for Step I (other than being able to determine axis deviation). Just recognize the overall patterns and know the treatment. Worry about guidelines and nuances when you're taking ACLS or as you go into your third year.

Oh, and take everything you read on these forums with a grain of salt.

wow thanks this is actually exactly what i was confused about, it's really clear now. Again thanks for the awesome explanation!

@jack shepherd is this book online?

 

[JackShephard MD]

...

 

[AndyRSC]

Yep, saying an 8-line paragraph for the sake of "normal-appearing QRS complex" is a wall of text, since no other parts of it were relevant. =)

 

[JackShephard MD]

.

 

[AndyRSC]

Since you quoted me at the beginning of that post, I figured you're addressing the wide- vs narrow-QRS portion, nothing more. Don't get your panties in a bunch.

 

[JackShephard MD]

Forget it. Your answer is good. Mine wasn't very relevant.

 

[AndyRSC]

Didn't I just explain it? I thought by quoting me, you're addressing the QRS width. If that was the case, while those pastes did briefly mention wide vs narrow, the text would be largely irrelevant.

If you had quoted the OP, I'd know you're pasting for him the underlying mechanisms of vtach and SVT, which I agree are important to understand.

 

[medman88]

Forget it. Your answer is good. Mine wasn't very relevant.

I thought your answer was useful, i wish you had kept it up. It was a little bit more in depth then the exact thing I was doing at that point (i.e. cardio from fa) but I was going to refer to it tonight when doing questions.

And yes I was asking if the book was free. Is it an online version? because you mentioned that you copy and pasted the answer from there.

 

[ijn]

Discerning vtach from SVT is probably beyond the scope of an exam for second year students. It's good to know in general, but it's just not that commonly tested on STEP 1. I wouldn't waste time beyond the classics - AV block, afib, vfib, and atrial flutter.

My exam had one EKG and it was totally unrelated to the question prompt. Granted, n=1 is worthless, but I haven't really heard of there being questions that require comprehensive EKG understanding.

 

[Phloston]

wt...f?

What are you confused about?

 

[AndyRSC]

Confused about where you could have copied and pasted that gem from.

 

[Phloston]

Confused about where you could have copied and pasted that gem from.

Lol, yeah...

I had a PBL tutor last year who was an ECG- and CXR-Nazi and wanted us to know that point hardcore for some reason.

I also read ECGs Made Easy during MS2.

 

[AndyRSC]

You may want to re-read it. Or get your money back from that tutor. What you said is completely backwards. All three parts of that quote need to be flipped.

 

[Phloston]

You may want to re-read it. Or get your money back from that tutor. What you said is completely backwards. All three parts of that quote need to be flipped.

Let me help you understand:

SVTs and BBB have prolonged conduction; the former is via the AV-node, as normal, and the latter is due to a His-Purkinje defect. Tachycardias of ventricular origin don't have prolonged QRSs because the electrical focus is downstream of the AV-node.

Your post is of only one type of VT, so before you flip out, try doing some reading first.

 

[AndyRSC]

Kay, that tells me you know heart anatomy 101, and not a ****ing thing about electrocardiography. Personally, I don't have a problem in the world with little bookworms who don't have **** for life experience being argumentative, but I do with you misinforming underclassmen, so shut your mouth, pull out an EKG or a phys book, get your facts straight, and then come back and tell me SVTs are wide- and VTs are narrow-QRS.

 

[Phloston]

Kay, that tells me you know heart anatomy 101, and not a ****ing thing about electrocardiography. Personally, I don't have a problem in the world with little bookworms who don't have **** for life experience being argumentative, but I do with you misinforming underclassmen, so shut your mouth, pull out an EKG or a phys book, get your facts straight, and then come back and tell me SVTs are wide- and VTs are narrow-QRS.

I just gave my justification above and you haven't refuted that. It is nevertheless correct.

The magnitude of the immaturity of your response, however, is quite impertinent and fairly disappointing.

 

[AndyRSC]

Your justification above is not an informed one. If you had bothered to type that (or 95% of the questions you ask here) into a search engine at any point today, you would have already known that.

It is nevertheless correct

Pretty mind-blowing. You are quite possibly the dumbest smart person I've seen post here in years.

Anyhow, post stupid **** all you want, all I ask is that you don't misinform underclassmen.

 

[Phloston]

I was wrong. The above SVT/VT statement is reversed. My bad for not having re-read what I had written before following through with everything else to support that.....not meaning to confuse people (or myself) here.

The only thing I actually find mind-blowing though is that you act as though you expect me to be perfect lol. I'm sure we all make mistakes, and I know for a fact I'll make a few stupid ones on Step1 (Gd forbid obviously).

 

[JackShephard MD]

Confused about where you could have copied and pasted that gem from.

Kay, that tells me you know heart anatomy 101, and not a ****ing thing about electrocardiography. Personally, I don't have a problem in the world with little bookworms who don't have **** for life experience being argumentative, but I do with you misinforming underclassmen, so shut your mouth, pull out an EKG or a phys book, get your facts straight, and then come back and tell me SVTs are wide- and VTs are narrow-QRS.

Wow. It's interesting to see how people behave when they're in a position of power. I can see you chewing out a nurse or janitor with the same lack of class displayed above.

Your justification above is not an informed one. If you had bothered to type that (or 95% of the questions you ask here) into a search engine at any point today, you would have already known that.



Pretty mind-blowing. You are quite possibly the dumbest smart person I've seen post here in years.

Anyhow, post stupid **** all you want, all I ask is that you don't misinform underclassmen.

I'm always surprised at how a small amount of medical knowledge + moderate academic success can lead to such pretentiousness and arrogance.

You're right but your behavior is childish and lacks class.

I thought your answer was useful, i wish you had kept it up. It was a little bit more in depth then the exact thing I was doing at that point (i.e. cardio from fa) but I was going to refer to it tonight when doing questions.

And yes I was asking if the book was free. Is it an online version? because you mentioned that you copy and pasted the answer from there.

I purchased the book on Amazon, electronic copy. I exited the convo because I anticipated what was brewing above. It's too bad that some believe that being right gives a license to be abusive.

 

[AndyRSC]

you act as though you expect me to be perfect lol

Nah, not at all. It's the last thing I would expect of anyone. Just that people fact-check what they write for misinformation. That's the only thing that I have little patience for, as you've probably noticed after many, many dealings with me =)
Like you, I also don't want to confuse or mislead anyone (including myself), so despite being ACLS certified for over 7 years now, I quickly checked that what I was saying is right early on in the conversation, just to be absolutely sure I'm not having a massive mental lapse.

It's interesting to see how people behave when they're in a position of power.

What position of power?

Look kiddo, I'm sorry about earlier. I tried to explain the misunderstanding to you, but you ran off crying. I'll work on lacking class, I promise, but for now:

 

[Phloston]

Just that people fact-check what they write for misinformation. That's the only thing that I have little patience for...

So according to this statement (and your grammar), you have little patience for people fact-checking what they write as potentially misinforming.

Ironic, because I would have expected you to check yourself there.

However, no more tears

 

[JackShephard MD]

What position of power?

Look kiddo, I'm sorry about earlier. I tried to explain the misunderstanding to you, but you ran off crying. I'll work on lacking class, I promise, but for now:

Alright Andy. I hope you enjoy your 4th year and match into whatever you're looking for.

Good luck.