Sunday, August 31, 2014

ECG Blog #96 (ECG Video-Blog-2) - ECG Diagnosis of Bundle Branch Block

     This is the 2nd installment of my ECG Video Blog. This 17-minute video reviews how to make the ECG diagnosis of BBB (Bundle Branch Block) in 5 seconds or less. Please Give Me Feedback ( as to whether you like this new Video format — which (if feedback is positive) I hope to use more to enhance my ECG Blog.
NOTE: There are advantages to using a video format format. These include:
  • Ability to illustrate concepts not done full justice by the written word.
  • Greater dispersion of my content through Google & YouTube. This material is free for anyone to use.
LINKS to my ECG Video-Blog installments:
  • ECG Video-Blog #1-Revised (= Blog #95) — Is there AV Block?
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  • ECG Video-Blog #2 (= Blog #96) — Bundle Branch Blocks
  •    Easy YouTube Link for Bundle Branch Block (
  •    Click Here for Timed Contents to Bundle Branch Block Video!
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  • ECG Video-Blog #3 (= Blog #97) — SVT with marked ST Depression
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  • ECG Video-Blog #4 (= Blog #98) — Clinical Arrhythmia Mgmt (Part I )
  • ECG Video-Blog #5 (Blog #99) — Clinical Arrhythmia Mgmt (Part 2 )
  • ECG Video-Blog #6 (= Blog #100— Clinical Arrhythmia Mgmt (Part 3 )
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  • ECG Video-Blog #7 (= Blog #101) — Wide Tachycardia + Chest Pain
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  • ECG Video-Blog #8 ( = Blog #105) — Basics of AV Block
  • ECG Video-Blog #9 ( = Blog #110) — Complete AV Block? / Laddergrams
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  • ECG Video-Blogs #10,11,12 ( Blog #113) — Rhythm Diagnosis Basics
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  • ECG Video-Blog #13 ( = Blog #116) — Essentials of Axis / Hemiblocks
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  • ECG Video-Blog #14 ( = Blog #117) — Brugada Syndrome
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  • ECG Video-Blog #15 ( = Blog #118) — QRST Changes
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  • ECG Video-Blog #16 ( = Blog #120) — Giant T Waves
    ECG Diagnosis of the bundle branch blocks can be simplified — and readily accomplished with accuracy in seconds. This is because: i) There are only 3 "answers" ( = typical LBBB; typical RBBB; or neither = IVCD); and ii) You only need to look at 3 leads to diagnose the type of BBB ( = leads I, V1, V6).
    • Recognition of the BBBs is thoroughly reviewed.
    • The system for rapid diagnosis is presented.
    • Practice tracings reinforce concepts (such as the 12-lead shown in Figure-1).
    Figure-1: 12-lead ECG. How would you describe the conduction defect? (Figure reproduced from A 1st Book on ECGs-2014-ePub). NOTE — Enlarge by clicking on Figures — Right-Click to open in a separate window.
    GTO – - on YouTube to view this ECG Video (17 minutes).
    • Click Here  — for a Timed CONTENTS of this Video on AV Block.
    • Please also check out my ECG Video Blog page on Google. The link is easy to remember = -
    NOTE: For a Power Point Show (.ppsx) version of my Video Blogs - CLICK HERE. This folder will contain links to download a .ppsx version that allows faster viewing:
      • Download the .ppsx to your computer desktop.
      • The PPT show is without automatic sound. YOU activate only the Audio clips you want.
      • Hover your mouse over the highlighted Audio. You may play and/or pause if/as you like.
      • Feel free to use this .ppsx for teaching with my blessings!


      1. HI Ken, always great job.
        A question on the last tracing seen on the video:
        You noticed as the I derivation pattern is not consistent wjth RBBB for the lack of terminal forces directed rightward; But, the fact that we have some signs of RBBB (v1,v6), signs of LAHB (s3>s2, rS complexes in inferior leads), and the I derivation is looking like a LBBB pattern, could we sospect some kinf of trifascicular block ongoing? Of course it is not complete block, otherwise the rhytm would be regular with Junctional escape, the irregularly of the R-R interval tells us that the Afib is conducting. But... can we be sure that this patient is not going to develop a complete AV block?
        Thanks for answer. Always your greater fan
        Niko G

      2. Thanks for your comment Niko. Of course one can never be "sure" about anything ... but the pattern of QRS morphology that we see in this last tracing ( = Figure-1 above) I believe is best called, "IVCD" — because it looks neither like RBBB nor LBBB. The term "IVCD" is a "catch-all" term. There may be a number of different etiologies for IVCD. For example, the patient may well have started out with RBBB (to give the pattern you note in leads V1 and V6) — but then had a myocardial infarction which resulted in development of the large Q in lead V1. Or there may be scarring from cardiomyopathy accounting for the atypical pattern. In contrast, the term, "trifascicular block" is one that is no longer recommended because it means different things to different people. BUT — if a patient has alternating bundle branch block (ie, one beat is conducted with LBBB — and the next with RBBB) — then we can say all 3 fascicles have been affected. That is a rare condition — and it is definitely not what we see above in Figure-1. Thanks again for you comment.