Right bundle branch block – Part 3

Let’s take another look at the ECG from Part 2.

RBBB_STEMI_01_wm

Does anything stand out?

How about lead V4?

RBBB_STEMI_01_V4

Here you can see the terminal deflection (blue arrow) is positive, and so is the T-wave (inappropriate T-wave concordance). There is also at least 1 mm of ST segment elevation. That’s definitely abnormal!

Now let’s look in the inferior leads. They all look abnormal, but I’m going to use lead aVF as the example.

RBBB_STEMI_01_aVF

The terminal deflection is negative (blue arrow) and the T wave is also negative (inappropriately concordant T-wave). The inferior leads are reciprocal to the anterior leads. Could this represent reciprocal changes? Absolutely!

It is sometimes said that reciprocal changes are of no value in the presence of bundle branch blocks. That’s not entirely true! You just have to interpret them within the context of appropriate T-wave discordance.

In other words, in the presence of bundle branch block, if the terminal deflection of the QRS complex is negative in lead III and positive in lead aVL, then you will have pseudo reciprocal changes (positive in lead III and negative in lead aVL). This is a normal finding in left bundle branch block, for example.

If, however, the terminal deflection of the QRS complex is negative in lead III (as in this ECG) and the same lead is showing inappropriately concordant ST-segment depression or T-wave inversion, then it’s probably not a pseudo reciprocal change.

I’d also like to point out that leads V2 and V3 look really strange in this ECG with a merging together of the S-wave and T-wave (sometimes seen in severe hyperkalemia). We would normally expect a terminal R wave in lead V2 with right bundle branch block.

Something’s going on here!

Let’s look at some serial ECGs. This one was taken just 4 minutes later.

RBBB_STEMI_02_wm

Here’s the final ECG in the series, recorded as the ambulance arrived at the hospital.

RBBB_STEMI_05_wm

Quite a difference! Once again, it’s easy to see the value of serial ECGs.

Let’s take a look at lead V2 and see how it changed from the first ECG to the last.

RBBB_STEMI_V2_serial_wm

See also:

Right bundle branch block: Part 1

Right bundle branch block: Part 2

Right bundle branch block: Part 3

13 Comments

  • Christopher says:

    Increase in inferior reciprocal changes along with changes in the ST segment in V2, V3, I, and aVL. Delta of the two 12-leads.

  • Tom B says:

    C. Watford – I wasn't sure what "delta of the two 12-leads" meant, but that was really cool! :)You'd think the good folks at Physio would include something like that as a product update.I've had similar ideas before, but I like the overlay concept.Nice work!Tom

  • Christopher says:

    Thanks, I was a software engineer long before a paramedic student, so this sort of thinking comes naturally. The only difficulty with taking a "delta" and doing "differential debugging" (to borrow a software term) on these 12-leads is rate changes. However, it is easy enough to pull a representative complex from each lead and superimpose it (I used Paint.Net).

  • Tom B says:

    That's true! I know from consulting for a certain implantable device company that changes in heart rate create problems for ST segment analysis, and not always for the reasons you might think! The biggest problem is rate-related changes in the QT interval, which changes the measured value for ST-segment deviation.As the heart rate increases, the QT interval shortens, so if you're measuring the ST-segment a prescribed distance away from the J-point (or R wave) then your measurement point creeps toward the T-wave.If the ST segment is upwardly concave (as it usually is) then as the heart rate increases, the ST-segment elevates, which can cause false positives.Tom

  • Ken says:

    Tom,Again I just want to say amazing. What a great clarification of RBBB. I was just berated by a "colleague" for calling a Code STEMI on a RBBB (Despite ACEP making a statement that patient's with BBB should err on the side of cuation). I wish I could have went back with this information in hand. Thanks for writing this stuff.- Ken

  • Tom B says:

    Ken -Thanks for the positive feedback! I'm glad you're finding the Prehospital 12 Lead ECG blog to be useful.Tom

  • Capeless Medic says:

    These ECG's show the absolute importance of performing serial tracings!  You said 'fortunately' this patient was delivered to a PCI hospital!? Did the paramedic not call a cardiac alert for the patient?  Looking at the initial 12-lead I may be hard pressed as well to activate the cath lab from the field, but there is definitely cause for concern with this patient.  The presentation along with the abnormal ECG findings would make me hit '12 lead' on the monitor like every two seconds!  The second tracing gives us enough 'at least in the system I work in' to activate the cath lab from the field.  Our protocols state that there must be 1mm of STE in two anatomically contiguous leads (I am sure similar to most other systems.) The receiving PCI hospitals really don't look at sending a patient off for intervention until there is at leas 2mm of STE in the precordial leads.  Enough going on….This is a great blog and I truly enjoy stopping in to progress my knowledge.
    Thanks for all of your hard work on this!

  • Dodge says:

    i just wish our service had 12 lead but it dosent have to rely on lead 2 and MCL not good enough for this day and age

  • Scarlett says:

    People in our area think that they are lucky that all the hospitals in this area have cath labs.  However….not every hospital in this area that has a cath lab also has cardiothoracic surgeons or trained OR staff who can do emergency open heart surgeries.  I asked a question once of such a hospital, why they had a cath lab but only a small OR that mainly performed outpatient procedures; their response was that "oh, if there is a major mistake made in the cath lab and the patient needs emergency open heart surgery, then we call an ambulance who takes the patient across town to a hospital that can do open heart surgery".  The hospital across town that can do open heart surgery… is about a 15 minute drive away, longer based on traffic, not to even include the time it takes for the ambulance to get there and load up the patient.  I doubt such a critical, hemorrhaging patient survives that ambulance ride….  
    So, if you are considering taking a patient to a cath lab hospital, I would also consider if the hospital has cardiothoracic surgeons in house or on stand by.  Just because you deliver a patient to a hospital with a cath lab, does not always mean that hospital is the best choice.  When I make my trauma or medical destination plan, I always consider more than just the ER or cath lab.  I think about the hospital's complete capabilities and what will give the best outcome for the patient.   I witnessed one night, a paramedic bring a MVA patient to a small town hospital, the guy had both femurs fractured.  That hospital had no orthopaedic surgeons on call, no OR on standby to handle the patient, their OR was closed for the night.  After over an hour of the ER doc acting like gee, what should we do? they finally had to airlift the guy to a trauma center.   I felt sorry for the patient, he suffered the whole time. 
    Sorry to be so long-winded here…

  • Shane says:

    Good stuff!! I had a patient with st depression in all leads but III and aVF. With RBBB. Chest pain was not controlled with nitro and morphine. Nitro drip amd labetelol for htn, flew him to chest pain center. What would cause this st depression in so many leads?

  • Andrew says:

    Are we not just concerned with the ST elevation in v4 ? Rather than the t was concordance ? Rbbb does not produce secondary st / t wave issues , so the presence of st elevation is worrisome enough I thought ?

    • Tom Bouthillet says:

      Right bundle branch does in fact produce a secondary T-wave abnormality but the J-point tends to be isoelectric. So yes, we should be worried about the modest ST-segment elevation in lead V4, but the concordant T-wave makes it even more worrisome, if that makes more sense. It’s just a single lead. It’s nice to see the serial changes to shore up the diagnosis, IMHO.

  • Dr Rambhai Agravat says:

    NICE information.
    Thanks.

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