Thanks for the comment! Bundle branch beats and hemifascicular beats should have a wider QRS duration because in order for the ventricle to be activated the impulse has to travel UP from wherever in the conduction system it's originating from, turn around at the His bundle, and then proceed down the other bundle or hemifascicles. That takes longer than if it started in the node or the His bundle itself, so the QRS should be wider.
wow, at first before watching the video, I thought it was a Mobitz Type 1 bcos there is a pattern of prolonging and a dropped beat. This is somehow new to me, a hemifascicular rhythm. Thank you so much. Honestly, I learned a lot from you and your strips are actual or taken from patients. A great way to learn. Can't thank you enough.
Hello, Shereen! Thanks for the compliments! It's funny, but now when I listen to this video I realize how far I've come as a teacher and as a media creator/producer... my ChalkTalks are all unique in that they come from real strips and so there are no two alike. Watch some of my newer ones on this channel (they're even better than this one) and I think you'll see that there's more to arrhythmias than what's in the textbook!
@xxxtazmanxxxx -- I sincerely apologize for that. I produced these videos so that people can continue to view them for years to come. I am in the process of developing the website, so it's not quite ready. But if you like my teaching style on these ChalkTalks, you'll really like the videos on the website! Stay tuned!
A clue as to where the beat originates from is that if the 12-lead morphology looks like a bifascicular block then the beat is coming from the remaining hemifascicle. Eg. if the escape beats resemble a RBBB/LPFB, then the beats are likely coming from the left anterior hemifascicle. As the beat travels up from there it makes the other two fascicles fire later (ie. delayed) giving the appearance of a bifascicular block. Hope that helps! -- Nick Tullo, MD
I still don't get why wouldn't it be high grade! If I understand correctly, in order to call it a type 2 second degree AV Block, we need to see atleast 2 QRS Complexes with the same PR Intervals and then the beag drops, but here we see a ventricular premature beat obscuring the P wave, then a Normally conducted P wave and then a dropped beat...We never got 2 normally conducted QRSs to judge if the PR Intervals changed or not! So shouldn't it be called High Grade Block? Thank You!
Hi! First, the wide QRS beat is not a ventricular premature beat-- it's not premature. It's an escape beat. It's presence hides our ability to see if the 2nd p-wave would have conducted or not, so all we see is one blocked p-wave. We cannot say if it's "Type 1" or "Type 2" because we cannot tell if the PR changes prior to the dropped beat since we don't see two PR intervals in a row to judge. I only referred to the prior ChalkTalk (#2) because that one showed Type 2. If you just saw this strip alone, you cannot tall Type 1 or Type 2. This is a complex case but we see escape beats that frequently throw our ability to "classify" AV block into neat little cubbyholes into chaos. That's why understanding what's actually going on is far better than trying to pin a label on the strip based on a classification algorithm. "High grade" implies that at least every other p-wave blocks, or that 2 P waves in a row block (i.e. 3:1) but we cannot say that here because the escape beat gets in the way. I hope that's a bit more clear.
That makes it so much more clear! Thank You Dr. Nicholas! I really enjoy learning from your videos! You have such flair for traching complex things, you make them all so interesting!
I think it can also be interpreted as a junctional complex (the one with the shorter R wave. If you look after the complex, an inverted p wave can be found, especially in v3. Or this can be interpreted as Wenckebach with some sort of electrical alterans or junctional ectopy.
I think the concept of a ventricular or fascicular escape complex traveling up and then back down the His bundle is incorrect. The increased degree of RBBB in the escape complexes is due to left to right conduction across the ventricular septum.
I had this diagnosed as 2:1 2nd degree Type II w/ junction escape beat. I see your reasoning to why it is a hemifasicular vs junctional beat. Good lesson. Do bundle branch beats normally have a longer QRS interval? And can you pinpoint based on morphology of the QRS where the beat originated: His, right, left?
@@marlenacakaa6868 Well, you would still consider it "high grade" second degree AV Block. It makes me wonder if there isn't some serious problem in or below the His bundle.
A little overly complicated explanation. As a former tele tech, the regular P waves, intermittent short pauses after the non-conducted P waves followed by ventricular escape beats jump out immediately. The dropped QRS complexes would make it a type 2 block. I would guess this person ended up with a pacemaker.
Thanks for the comment! Bundle branch beats and hemifascicular beats should have a wider QRS duration because in order for the ventricle to be activated the impulse has to travel UP from wherever in the conduction system it's originating from, turn around at the His bundle, and then proceed down the other bundle or hemifascicles. That takes longer than if it started in the node or the His bundle itself, so the QRS should be wider.
wow, at first before watching the video, I thought it was a Mobitz Type 1 bcos there is a pattern of prolonging and a dropped beat. This is somehow new to me, a hemifascicular rhythm. Thank you so much. Honestly, I learned a lot from you and your strips are actual or taken from patients. A great way to learn. Can't thank you enough.
Hello, Shereen! Thanks for the compliments! It's funny, but now when I listen to this video I realize how far I've come as a teacher and as a media creator/producer... my ChalkTalks are all unique in that they come from real strips and so there are no two alike. Watch some of my newer ones on this channel (they're even better than this one) and I think you'll see that there's more to arrhythmias than what's in the textbook!
@xxxtazmanxxxx -- I sincerely apologize for that. I produced these videos so that people can continue to view them for years to come. I am in the process of developing the website, so it's not quite ready. But if you like my teaching style on these ChalkTalks, you'll really like the videos on the website! Stay tuned!
A clue as to where the beat originates from is that if the 12-lead morphology looks like a bifascicular block then the beat is coming from the remaining hemifascicle. Eg. if the escape beats resemble a RBBB/LPFB, then the beats are likely coming from the left anterior hemifascicle. As the beat travels up from there it makes the other two fascicles fire later (ie. delayed) giving the appearance of a bifascicular block. Hope that helps!
-- Nick Tullo, MD
I am an ICU RN in a general ICU. I am wanting to work towards more of a Cardiac ICU, Thank you for breaking down ECG the way you do. It truly helps.
I like the way u explain everything. You are amazing!!!!
i'm so weak in this. hope I can learn much from here.
@striae -- Thanks for your comment, but I'm not sure what you are asking.
This was helpful just breaking it down in steps. Thank You
You're welcome! I'm glad you found it helpful!
Your are awesome..please keep posting
Hey, Pranav! Thanks!
Boy. That chalk talk was complicated. I will have to listen to that one many times. 🤪
fantastic and very clear lesson! thank u so much!
So...what was it?? A beat originated somewhere in the purkinjes? It doesnt fall in any of the categories below?
Wouldn't this strip be high degree AV block with 3:1 conduction?
It is. U r absolutely correct
great work indeed. very very helpful
awesome video.
I still don't get why wouldn't it be high grade! If I understand correctly, in order to call it a type 2 second degree AV Block, we need to see atleast 2 QRS Complexes with the same PR Intervals and then the beag drops, but here we see a ventricular premature beat obscuring the P wave, then a Normally conducted P wave and then a dropped beat...We never got 2 normally conducted QRSs to judge if the PR Intervals changed or not!
So shouldn't it be called High Grade Block?
Thank You!
Hi! First, the wide QRS beat is not a ventricular premature beat-- it's not premature. It's an escape beat. It's presence hides our ability to see if the 2nd p-wave would have conducted or not, so all we see is one blocked p-wave. We cannot say if it's "Type 1" or "Type 2" because we cannot tell if the PR changes prior to the dropped beat since we don't see two PR intervals in a row to judge. I only referred to the prior ChalkTalk (#2) because that one showed Type 2. If you just saw this strip alone, you cannot tall Type 1 or Type 2.
This is a complex case but we see escape beats that frequently throw our ability to "classify" AV block into neat little cubbyholes into chaos. That's why understanding what's actually going on is far better than trying to pin a label on the strip based on a classification algorithm. "High grade" implies that at least every other p-wave blocks, or that 2 P waves in a row block (i.e. 3:1) but we cannot say that here because the escape beat gets in the way. I hope that's a bit more clear.
That makes it so much more clear! Thank You Dr. Nicholas! I really enjoy learning from your videos! You have such flair for traching complex things, you make them all so interesting!
is this patient having PVCs? because of the av block so when the SA shoots again then the ventricle fires on its own? idk if I'm making sense
I think it can also be interpreted as a junctional complex (the one with the shorter R wave. If you look after the complex, an inverted p wave can be found, especially in v3. Or this can be interpreted as Wenckebach with some sort of electrical alterans or junctional ectopy.
I think the concept of a ventricular or fascicular escape complex traveling up and then back down the His bundle is incorrect. The increased degree of RBBB in the escape complexes is due to left to right conduction across the ventricular septum.
you keep saying to go to the website but I go there and I can't sign up. log in or subscribe so therefore the website is useless at this point
I had this diagnosed as 2:1 2nd degree Type II w/ junction escape beat. I see your reasoning to why it is a hemifasicular vs junctional beat. Good lesson. Do bundle branch beats normally have a longer QRS interval? And can you pinpoint based on morphology of the QRS where the beat originated: His, right, left?
isnt it resumed on the qrs notch in v1 lead?
super
Thanks! Keep watching my videos -- there are a lot of them!
I don't understand why it is not a high grade av block 3:1?
You can't call it 3:1. Where is the third p-wave that blocks? The junctional beat gets in the way so you can't tell what would have happened.
@@ECGDoc Okay, now I get it. Thank you :))
@@ECGDoc How can we call ECG when there is a 2:1 block and then we got a 4 blocks p-wave and then again it coming back to 2:1?
@@marlenacakaa6868 Well, you would still consider it "high grade" second degree AV Block. It makes me wonder if there isn't some serious problem in or below the His bundle.
A little overly complicated explanation. As a former tele tech, the regular P waves, intermittent short pauses after the non-conducted P waves followed by ventricular escape beats jump out immediately. The dropped QRS complexes would make it a type 2 block. I would guess this person ended up with a pacemaker.