Friday, November 16, 2012

Chest Pain and Right Bundle Branch Block. What is the Diagnosis?

A male in his 70's with no h/o MI or CAD presented with new onset chest pain.  Here is his ED ECG:

There is sinus rhythm and right bundle branch block, and ST elevation in V1-V3. 
Normally, RBBB has ST depression in right precordial leads, especially V2 and V3 (see ECG below).  Sometimes it is isoelectric.  But if there is any ST segment elevation, as in this case, it is STEMI (or RBBB with old MI and persistent ST elevation) until proven otherwise.

Baseline RBBB (normal RBBB, no STEMI). Note that there is a large R' wave in V1-V3 and discordant (opposite direction of QRS) ST segments. (Thanks to K. Wang's EKG Atlas for this image)

The emergency physician was very worried about STEMI, called the cardiologist on call, and they performed an immediate bedside echo which confirmed absence of anterior wall motion.  Immediate angiogram was done and confirmed LAD occlusion, which was opened and stented.

Here is another example.

Here is a 3rd example.

Here is a 4th example.


  1. I noticed also some ST depression in V5-V6. Is this normal? Normally the ST segment in both of that leads would be isoelectric/ slightly elevated. Am i wrong?

    1. That is correct. There is also a moderately hyperacute T-wave in V4.

    2. So could the ST depression in V5-V6 mean that there is some peri-infarction ischemia occuring in lateral area as well ?

    3. That is uncertain. As I have pointed out on many previous posts, ST depression does not necessarily localize subendocardial ischemia. Also, ST depression can be a manifestation of occlusion, as with de Winter's T-waves. The ST depression does, however, lend more evidence to the presence of any ischemia.

  2. This is a fascinating case, Dr. Smith, and your explication of the essential features is as usual brilliant. Thanks. The patient does seem to also have left atrial enlargement, probably a result of mitral valve disease (stenotic, severely regurgitant, or mixed); this is evidenced by p mitrale - seen in all the limb and augmented limb leads - and the biphasic and terminal negative p wave in V1. There is no evidence of AF in this ECG. Interestingly the PR interval appears a touch short to my eye in some of the leads, especially the lateral precordials. Is that a delta wave in V2? I wonder if the LA enlargement was related to the STEMI. Did he have any visible thrombi in the LA?

    1. Good comments. Yes, the p-wave do suggest LA hypertrophy. I unfortunately do not have access to the echo, but the patient was very healthy and athletic with no h/o cardiac problems. I do not think the PR is short (see lead II). What you are seeing that looks like a delta wave is the R' wave of the RBBB that has a slow initial depolarization.
      Steve Smith


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