Intro to EKG Interpretation - Bundle Branch Blocks 

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!

its been 9 years and we still benefits from this. thank you.

Thank you Eric. It's so incredibly visual and clear explained

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.

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!

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.

Loved the summary at the end!:)

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.

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!

Thank you. You create the best videos!

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.

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

Don't understand the dislikes! Thank You Amazing lecture.

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.

Thanks for the great information!

Great lecture!

Very well explained. Thank you.

Great, simple and clear

THIS is great thank you

Thanks a lot for this informative lecture.

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

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.

***** 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.

Masterpiece !!!!!!

Thank you very much Dr Strong

so helpful! Thank you

Thanks for great explanations

GOAT ekg lecturer

Thank you very much for this lecture

Great lecture, thanks!

very helpful lectures.

Thanks ! Great job!

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

Could you list the EKG criteria for Trifascicular block? i understand there can be several different combinations of individual blocks. Ty!

thank you respected. sir it's really very helpful that I can't describe words

Nice work......

The best video on BBB

Excellent!

3 am and non medical person watching this for no reason. Irony

Awesome, thanks sir.

very helpful. thanks

6:48 "A tall, single R wave in v6"! What's their number? ;)

In the V1 lead, is there a reason why we see an upslope of the PR interval?

Very well made 👍

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!

Thanks Dr Strong

Thanks for this information

thank you very much .

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?

great video, but your diagram @ 4:05 is a bit confusing, a top down view would be better.

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....?

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?

Thank you so much.

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.

Thank you so amazing

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)

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

Could you highlight the changes on the EKG strip itself you are describing @8:40 and @9:50

In LBBB ,why initial deflection in V1 is negative? Please reply.

Thank you.

Thank you!!!

Thanks!

in the last one how come v1 dosent have the criteria for RBBB

Thank you Sir

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

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.

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 ?

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.

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

Well done

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 ??

There is a mistake with SAX anatomical diagram in the segment of fascicular bocks. I think the septal and lateral walls are wrongly labelled.

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?

Could someone please explain to me the reason for st elevation in lbbb?

Can a branch block ever be normal? Or is it always a serious problem?

Professor, can you do a video about eeg interpretation?

Can you diagnose a QT prolongation with a bbb?

In the EKG for Bifasicular block, I dont see the RBBB... Am I missing something?

Nice

Please upload remaining advanced EKG interpretation videos

What do you mean by poorly defined conductive tissue?

good shizzle

good

best

👍

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

I like your teaching. But I have a comment that plz teach by point like ecg Graf.

Are you the goddess of EKG?

Thanks so much for your videos! any chance you can email me your powerpoint presentation?

That’s hard😞

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.

16:47

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,

I keep hearing "deep-ass wave"

Any one from today?

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