Tuesday, January 12, 2010

Right Bundle Branch Block (RBBB) with Anterolateral STEMI

A 62 yo male with h/o CAD and stent in 1st OM presented with Chest pain while biking. Vitals were normal. An ECG was recorded:

There is Right Bundle Branch Block with large R-wave in V1 (the first R wave of the rsR' is not present) and wide S-wave in lateral leads I, aVL, V5 and V6. There is a slight amount of ST elevation (1 mm) in lead V3, and slightly more in V4-V6. The T-wave is upright in leads V2 and V3. Usually, but not always, RBBB has an inverted T-wave with up to 1 mm ST depression in leads V2 and V3, so these upright T's with slight ST elevation is highly suspicious for anterior STEMI. The ST elevation in lateral leads is diagnostic.

In this case, the diagnosis was particularly easy because there was a prior ECG available:

Here the normal baseline is easy to see for comparison. There was an rsR' before (now the first R may be lost because of anterior wall ischemia), there was T inversion (normal) and ST depression (normal) in V2 and V3. There was no ST elevation in lateral leads (there never should be in RBBB).

The cath result was complex, but suffice it to say that there was TIMI-2 flow in the LAD by the time of cath.


  1. Are voltages as low as those seen in the presentation ECG common in RBBB alone, or are they yet another finding concerning for ischemia? Thanks

    1. Eric,
      No, they are not common in RBBB. Probably related to patient habitus, etc. This is why ratios are so important. The T-waves are not large either, but in comparison to the QRS, they are!

      Steve Smith


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