Intro to EKG Interpretation - Bundle Branch Blocks
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- Опубліковано 19 гру 2012
- A lecture on intraventricular conduction delays, including bundle branch blocks (complete and incomplete), fascicular blocks, and non-specific intraventricular conduction delay. Major etiologies of these diagnoses are reviewed as well. I highly recommend watching it in full screen mode in 1080p.
Hi there, I'm a junior off-service resident on my first internal medicine/cardiology block of the year. I really appreciate the video. The clearest explanation of Bundle Branch Blocks that I've found. Thanks, and I will definitely recommend to my junior colleagues!
Thank you Eric. It's so incredibly visual and clear explained
its been 9 years and we still benefits from this. thank you.
thank you! I have really enjoyed this series. your videos are the BEST ! Laid out in such a simple straight forward way!
Jason, thanks for the feedback. I thought about a couple different approaches to the organization of that diagram, but maybe didn't choose the best. I'll try a different one the next time one of the EKG lectures calls for it.
Thank you for the lovely video ! Just a bit of feedback .. I can see that left and right are indicated as per anatomical norms in medical illustrations - left of the image is on the same side as the viewer's right hand . However , this convention is true only of images of human anatomy viewed antero - posteriorly and not for those viewed postero- anterioly as the chest wall seems to have been drawn here . It got me confused and I had to rework my understanding after correcting for it . Thank you ! { I see now that my comment is 8 yr too late , but nvm }
Extremely useful for medical students. Helping me a lot for my cardiology rotation. I really enjoy these lectures. amazing stuff. Very well explained. it couldnt be clearer.
I finally found what I was looking for! Love the explanation with the comparison between EKG, location of the heart and precordial leads! Thanks a lot.
Excellent. You're better than my mentors when I was in residency and fellowship! Thanks!
Amazing content - incredibly informative & educational. PUT MORE QUIZES AT THE END TO HELP the people who watch to understand the knowledge better. The way you set up the Quiz for Chamber Enlargement was phenomenal. Pocket Brain by Ken Grauer is top notch btw.
Thanks for the feedback. I'm still working on new EKG videos, along with other med topics, but I hope to create a couple of "EKG quiz videos" for self-assessment with all of the high quality EKGs I have left over that haven't been used in any of the preceding, more didactic-type videos. It's probably some time away before I create and post them, but definitely my intention. Glad you've found Pocket Brain helpful!
Loved the summary at the end!:)
I thought I will never understand EKG before I watched your videos! Thank you so much! you are much better than any book! Very helpful!
💙💙⛈💙⛈💙😜💙😜💙🤢😂⛈😂⛈😂⛈😂😜😂⛈😂😜😂😔😉😉😔😉😔😉🤣😔😉⛈😘😜😉😜😂😍😜😍🤷♀️😜😉😜😉😔😔😍😔🎃🤦♀️🎃⛈🎃😔🎃😔🎃⛈🎃⛈🧧🥈🥈🧧🥈🧧🥈🧧🥈🧧🧧🥈🎗🎗
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Kitchen good thing hit the
Thank you. You create the best videos!
brilliant it is the best ECG explanation i ever heard Thanks a lot
it would be great if you explained the whole ecg in such way
Thank you. Great lecture.
In the post-Soviet countries there are no such videos.
I actually like the perspective you used. It was useful to reinforce the perspective of looking at CTs.
Thank you! I don't know why it's so difficult to find a step-by-step explanation of this pathology.
Thank you very much Dr Strong. Good lecture.
Don't understand the dislikes! Thank You Amazing lecture.
Voice is Higher pitched Monotone. Also, assuming that we get bits that are not well taught.
😀
Right? Either provide constructive criticism or move on. People are just rude.
Hi Thanks for the lecture very helpful.
What I would like to see is to show on the actual ekg what you mean with a red cursor preferably. This would be much clearer than just talking about it!
Thanks again
Thanks for such an informative video, which definitely helps to remember tough concepts for exam preparation. Here are
2 concerns about LBBB diagnosis
1)There should be a QS or rS complex in lead V1
2)T wave concordance
Thanks for the great information!
***** Trifascicular block has very subtle variations in how it's defined by different sources. The most commonly cited definition is: trifascicular block = RBBB + (left anterior fascicular block OR left posterior fascicular block) + 1st degree AV block. However, as per my wife (an electrophysiologist), it's best defined as: trifascicular block = RBBB + (LAFB OR LPFB) + (1st degree AV Block OR type 1 2nd degree AV Block). Most cardiologists, my wife included, don't like the term trifascicular block since block of all three fascicles (e.g. right bundle branch, left anterior fascicle, and left posterior fascicle) would necessarily result in complete heart block. In addition, even if one uses the infrequent term "incomplete trifascicular block" to refer to the situation where conduction in the 3rd fascicle isn't completely blocked, but just slowed (i.e. the definitions above) - it's still misleading because the AV block one sees in this situation may actually be located in the AV node, and not in the 3rd fascicle as implied by the term. In summary, trifascicular block is a term with which clinicians should be familiar, but shouldn't necessarily use themselves.
thank you respected. sir it's really very helpful that I can't describe words
hello bai sab mara b left bandel branc black ha lakin is English ke moja smj ni i kay ap bta saqta ha ka English ma kay bta rha ha
Very well explained. Thank you.
Great lecture!
Great, simple and clear
Thanks a lot for this informative lecture.
THIS is great thank you
Masterpiece !!!!!!
Thank you very much Dr Strong
3 am and non medical person watching this for no reason. Irony
Thanks for great explanations
so helpful! Thank you
Great lecture, thanks!
Thanks ! Great job!
Thank you very much for this lecture
GOAT ekg lecturer
very helpful lectures.
Awesome, thanks sir.
The best video on BBB
Excellent!
hello! trying to come to terms with all blocks this morning. Is there always an axis deviation with fascicular blocks? that is if i first look at axis, then eliminate either a LBBB if there is a left axis, then a partial block could the next step be eliminating a left posterior fascicular block? I'm trying to understand the relationship with axis and fascicular block.
Nice work......
I had an EKG in the ED the other day and it had a clear left anterior fascicular block, it also had ST elevation in V1-V3 (present on the old EKG as well). It also had broad R waves in I and aVL and no q waves present in V6. Can you have a incomplete LBBB and LAFB together. Thank you. Your lectures are extremely helpful in the explanations, making it much easier to remember everything.... thank you!
Hi I have this did you find out much information ?
Very well made 👍
I don't understand the orientation of the transverse section of the heart and placement of precordial leads. If the placement of the precordial leads indicates the front of the body ("top") then the heart and the leads are on the right side ...? if , on the other hand, the front of the body is on the "bottom" , then the precordial leads appear to be placed on the pt's back....?
MRT-like view! Imagine you draw it on a piece of paper like your usual transversal plane (posterior view). If you take the very same piece of paper and flip it to get to the back side (and see through) then you'll get the section in the video.
Hope this helps.
Its the same image you see in a CT scan, a transverse view of the body seeing from below.
very helpful. thanks
Thanks Dr Strong
thank you very much .
Thanks for this information
Thank you so much.
I find it strange that Ventricular Depolarization in V1 would be Negative rather than Positive. Does LV still have a stronger vector than RV during LBBB, just that the whole process is prolonged?
Yes. The mass of the LV is still the same in LBBB as it would be otherwise, so the vector sum is still in the same direction overall. The bundle branch block just makes it take lomger, and eliminates the septal q waves.
Eric's Medical Lectures I understand that the vector sum is in the same overall direction but still why is there not an initial positive deflection in V1 (and neg.deflection in V6) if the right ventricle is depolarized slighty before the left ? And why is the slow depolarization of the LV more or less concurrent with the fast depolarization of the RV (as for RBBB you said there was unilateral depolarization of the LV) ?
Answer appreciated!
Could you list the EKG criteria for Trifascicular block? i understand there can be several different combinations of individual blocks. Ty!
Thank you!!!
Thank you so amazing
Thank you for the information! I'm wondering why there wasn't a normal EKG to compare. I wanted this information for my own knowledge. It was hard to differentiate when there was nothing "normal" to compare to.
Well then learn what a normal ECG should look like and you will never need a picture of it again.
Totally agree, can't find a normal ECG with all waves labelled on the net; would sometimes really help.
+Mimicakes don't listen to the critics. Sometimes people forget what it's like when you are still learning.
Thank you.
In the V1 lead, is there a reason why we see an upslope of the PR interval?
in rbb you explained as the electrical impulse crosses bundle of his, it passes the interventrical septum from left to right and gives a small positive deflection r wave in v1. q wave is due to septal depolarisation, not r wave . first positive deflection the r wave is due to left ventricular depolarisation and 2nd r wave is due to delayed right ventricular depolarisation in lead v1. there is two qrs complexes of left and right ventricles attached to each other but occuring seperately
Thanks!
Does bundle branch block(s) sometimes manifest after traditional open heart surgery such as for mitral or aortic valve replacement with prosthetic valve?
BBBs or fascicular blocks common in survivors of Myocardial Infarction?
I assume that the affected chamber does not pump blood as efficiently if it has BBB? Does it affect ejection fraction?
Hello Dr. Strong, I'm wondering
“Why in LBBB , the right ventricular depolarization didnt show positive deflection in V1 and negative deflection in V6.
The final broad S in V1 and broad R in V6 seems like that the EKG pattern was more affected by the last portion (the delayed left ventricular depolarization through cell to cell propagation)
Maybe because of depolarization of the apex of the heart, when the rbb carries the charge to the rv, the apex is depolarized first which depolarizes away from V1, and then, probably, goes and depolarizes the LV in the same time with RV thus you get the very wide QRS and *stemi like features* as in Lv takes a long time to depolarize, again because Lv is being depolarized outside to inside instead of the normal inside to outside (from LBB)
Not 100% sure about this, but that's my educated guess as to why this particular thing happens
great video, but your diagram @ 4:05 is a bit confusing, a top down view would be better.
6:48 "A tall, single R wave in v6"! What's their number? ;)
Thank you Sir
Could you highlight the changes on the EKG strip itself you are describing @8:40 and @9:50
What are the complications of having a RBBB? Is it reversible/fixable? I was first diagnosed RBBB with 80-100ms and then in a course of 6 months progressed to a 120ms (right on the verge between complete and incomplete) and I am quite worried. I have none of the etimologies and the block just randomly appeared when I was 15 (I never had it when I was smaller because of other EKGs). I am nearly 18 now. Getting checked again in Jan 24th.
***** I'm very sorry, but I'm not able to offer specific medical advice on here. However, in most cases, bundle branch blocks are not reversible, but they are also not problematic themselves. Instead, they can be indicative of underlying cardiopulmonary disease, and should prompt the physician/provider to consider possible causes. There are certainly a fair number of people who have idiopathic bundle branch blocks, which means that no underlying cause can be identified. I would discuss it with your doctor. I'm sorry that I'm unable to be more specific.
Thank you for the quick response. You are amazing man! Keep up the good work :)
I agree totally with Zaid Mouse. The V1 electrode should be picking up a faster positive deflection than the left side as the Left bundle is blocked....... only afterwards receiving slow deplorization after the V1 has shown upward (positive deflection) ???? I don't understand that negative deflection at all ...... something wrong there for sure
Well done
In LBBB ,why initial deflection in V1 is negative? Please reply.
in the last one how come v1 dosent have the criteria for RBBB
Hi doctor strong , why there is bifascicular block at the end of the video? There is no EKG finding of M shape in V1. thank you
Sir ,in the last example of bifascicular block
In V1 there is no M pattern(rSR)
In I and aVL there is no prominent S wave we just have one finding supporting RBBB ie qrs >120ms so how can I come to a fair conclusion ?
Actually there is rSR finding in V1 watch the video in better quality may be 480p or more you will see its there
Thank you for this excellent video. I have a question, why there is T wave inversion in RBBB? Repolarization current is negative and is moving away from the leads, so the T wave should be positive.
Thank you for the video on BBB
I like to ask one query on the LBBB. Not only seeing your video but many other videos on the LBBB have not cleared my confusion.
It is said in the left bundle branch block the left ventricular depolarization is delayed and the right ventricle starts to depolarized first. This is the most fundamental fact in LBBB. In the normal heart, both ventricles depolarize simultaneously and since Left ventricular forces being very much stronger the net direction of depolarization is towards the left leads.
Another fundamental fact is if the depolarization passes in the direction of the lead show an upward deflection for that lead, and if depolarization passes away from the lead shows a negative for that lead. These two fundamental facts I am assuming you and everyone agree.
Since in the left bundle branch block the left ventricle depolarization starts a little later than the right ventricle, after the p wave, we should see in lead V1, a first upward deflection; and in V6 a downward deflection in the ECG to indicate the right ventricle. The left ventricular contribution should come a little after the right ventricle.
But the ECG does not show that. It shows directly an S wave in V1 and an R wave in V6. The only explanation possible is in spite of the left bundle branch block the speed of impulse conduction is still on par with the right.
I hope as a teacher you realize it is an important fact that must be clearly explained, as the ECG is in contradiction to both fundamental principles.
I love to have your explanation and hope you would clear my confusion on this.
The initial part of the QRS complex is due to depolarization of the intraventricular septum (before the bulk of either ventricle is depolarized). Normally, the septum is depolarized from the left bundle in a left to right direction. Thus, normally V1 has a small positive r wave, while I, aVL, and V6 have small negative q waves (i.e. "septal q waves"). However, if the left bundle is not working, there is time for the slightly slower right bundle to depolarize the septum instead. Since septal depolarization in this case proceeds from a right to left direction, V1 lacks its normal initial r wave, and the lateral leads lack their normal septal q waves.
@@StrongMed Thank you so much for your quick reply.
So do you mean to say the septal deflection and the right ventricular deflection being in opposite directions get cancels off, and so both contributions are not seen on the ECG and only the left ventricular component is displayed on the ECG?
Oh dear...when I tried to understand the precordial leads I was looking for a vectorcardiogram in the transversal plane for ages and ended up drawing one all by myself... and you got it in a later video?
There is a mistake with SAX anatomical diagram in the segment of fascicular bocks. I think the septal and lateral walls are wrongly labelled.
I was confused at first too, but it's seen from the perspective of the apex I think - this picture explains it images.google.com.au/imgres?imgurl=https%3A%2F%2Fi.pinimg.com%2Foriginals%2Fb0%2F0c%2F97%2Fb00c9722e8a52bae4ed14e73b0ff1125.png&imgrefurl=https%3A%2F%2Fwww.pinterest.com%2Fpin%2F161848180338909037%2F&docid=yMG-froLyRkErM&tbnid=ddFuvQMEJzA-WM%3A&vet=1&w=400&h=347&source=sh%2Fx%2Fim
If bufasicular block is due to right bundle branch block and left posterior hemiblock, there will be RBBB and right axis deviation is it true ??
Can a branch block ever be normal? Or is it always a serious problem?
Could someone please explain to me the reason for st elevation in lbbb?
Nice
Love all the lectures but this one is little chaotic, that would be great if you circle things we need to look at. Also with Bifascicular Block on the last strip I don't see RBBB anywhere and there is no explanation why it's different from "classic" RBBB
Thanks for the feedback. This was one of my first EKG videos and I agree that it's not one of my best. If I ever have time (which doesn't look like it will soon), it's on my short list to redo.
@@StrongMed Thank you for the reply, I really enjoy your videos and thank you for what you are doing
What's typical for RBBB + LAHB is an overall negative complex in lead II. In case of RBBB + LPHB there would be a steeper descent of the S wave in lead I as well as rather tall R waves in leads II & III.
best
In the EKG for Bifasicular block, I dont see the RBBB... Am I missing something?
The 3 criteria are all there: Widened QRS complex, an M-shaped complex in V1 (the notching of the R wave is subtle in this example, but present on the upstroke), and prominent S waves in the lateral leads (prominence here is relative; in other words, even if the S isn't usually deep, it's relatively deep compared to the overall QRS amplitude in that lead *and* it's relatively prolonged compared to the normally very short duration S waves)
@@StrongMed thanks for responding.
Please upload remaining advanced EKG interpretation videos
udaya v I'll be posting them interspersed among other topics over the next 12 months (probably about one EKG video per month).
good shizzle
Professor, can you do a video about eeg interpretation?
I'm sorry, but I have no familiarity with reading EEGs.
good
What do you mean by poorly defined conductive tissue?
There exists multiple conductive tracts that connect the SA node to the AV node. They are poorly defined in the sense that they cannot be anatomically dissected and identified as easily via pathology as can the His-Purkinje system. They also probably vary greatly from person to person. Their existence is largely inferred by the fact that premature atrial contractions arising from ectopic foci are often followed by a prolonged PR interval, suggesting that the wavefront of depolarization does not conduct as effectively/quickly from atrial tissue to the AV node as it does from the SA node to the AV node.
Eric's Medical Lectures
Thank you for great lectures
Love them
I teach students too and found these to be most helpful in imagining the whole thing.
Dr. Job
Can you diagnose a QT prolongation with a bbb?
+Christine Bell That's a great question, and a source of confusion among everyone from students to faculty. The short answer is maybe. Sometimes if the QRS is a little wide, you can measure something called the JT interval (i.e. the time between the J point and the end of the T wave), and correct it for heart rate like you would for the QT; a JTc > 330ms is considered unusually prolonged, with the same significance as prolonged QT. But if the QRS is extremely wide, and the resulting T wave is highly unusual as a consequence of a secondary repolarization abnormality, there's no clear consensus on how to define a prolonged QT. At some point, I'll be making a video that discusses the QT interval and QT prolongation, and will review the literature more in depth for that.
Thank you. I love your videos!
Are you the goddess of EKG?
I like your teaching. But I have a comment that plz teach by point like ecg Graf.
👍
That’s hard😞
Thanks so much for your videos! any chance you can email me your powerpoint presentation?
Sir, your comment showed up in my UA-cam notifications just now (time stamp 42 min ago), yet the time stamp on it when viewed here on the video page is 2 years ago. In other words, I have no idea how old this comment is... However, unfortunately, I no longer provide my PowerPoint presentations to viewers because I've caught far too many people plagiarizing them (including college and med school profs!). A significant number of the videos have been converted to pdf documents, which are available on a public Google drive here: drive.google.com/drive/folders/0B9SDUwepGWeUTmtscnJSSjR5OE0
As I am hoping to eventually create a book on ECGs out of the material from the ECG videos, they are not included.
@@StrongMed so good of you!
I keep hearing "deep-ass wave"
Any one from today?
Over all good try to explanation but, wanted more elaboration on graph of V1 to V6 of both RBBB AND LBBB with animation ray, onto the lines of graph and direction, em trying to talk about 4.00 to 7.00 minute duration, want a little more added sentences and effort, worth rating 95% to your video,
16:47
Ppppp