63 Year Old Male: "Dental Pain" — Discussion

This is the discussion to "63 year old male: "Dental Pain". You may wish to review the case.

For starters, i think we all agree that the patient, with his signs and symptoms, needs to be transported. We have all had patients like this who don't want to go, even though we know they should. Patients say they don't want to go for different reasons… some want to use us as a "litmus test", gauging their need to go by our reaction. Others don't want to put us through the trouble. Some are afraid of not coming home, and some, just plain don't want to go. We have to do everything possible to convince them to go, and as we know, sometimes that requires quite a bit of persistence!

Now, about that 12 lead:

There is sinus rhythm, with a rate of about 80 and a normal PRI. The QRS is wide (124ms). There is Right Bundle Branch Block, with an rsR' in V1, and s waves in I and V6. 

Do we see any other abnormalities on the 12 lead? RBBB should have T waves appropriately discordant to the terminal portion of the QRS. There should be no ST elevation in the right precordials…  in fact, you might expect a slight bit of ST depression in V1 and V2 opposite the QRS. For the most part though, the ST segments are not deviated as they are in LBBB, which makes it possible to assess ST segments normally. Let's take a look in V1 and V2:

There is a slight amount of ST elevation in V1. This is not normal. V2 has concordant T waves, without ST elevation, which is also concerning.

Is this an anterior STEMI? Not so fast… let's see what the rest of the 12 lead shows:

There is ST elevation in aVR (about 2mm)  and slight ST elevation in V1, with ST depression in leads I,II,III,aVF and V3-V6. This constellation of "global" ST depression with ST elevation in aVR and V1 is typical for subendocardial ischemia. Could it be posterior STEMI? Not likely in this case. The anterior ST depression of posterior STEMI is usually maximal in V2-V4, and that is not the case here. It looks different as well. It helps me to visualize the direction of the ST segments. Think about where the ST depression is: inferior and lateral. What would be reciprocal to inferior and lateral depression? Rightward and superior ST elevation, which is exactly what we see here. This is what it looks like on the hexaxial reference system:

 

We see the direction of ST depression (blue arrows) and the reciprocal ST elevation (red arrows).  You can't have a STEMI in aVR, so you can see this is just opposite the diffuse ST depression. In the precordial leads, the lateral ST depression is opposed by the slight ST elevation in V1. This would not be considered a  STEMI.

This pattern of diffuse subendocardial ischemia could be due to a left main lesion, proximal LAD lesion, or 3 vessel disease. We can not tell from the ECG. People rarely survive long with a left main occlusion, which makes that unlikely (unless there was much collateral circulation). The most common issue is left main ACS, which is not a STEMI equivalent.

In the field, we treat this patient for ACS with our standard meds… For some agencies that carry Clopidogrel, probably not a good med for this patient in case he needs CABG. At the hospital, he won't get thrombolytics because it is not STEMI. Most likely he will be medically managed, with PCI to follow if medical management doesn't work, or his symptoms worsen.

Unfortunately, we don't have an outcome for this patient, but he crew was able to convince him to be transported.

For more information on subendocardial ischemia, read this great post by Dr. Smith.

2 Comments

  • Dr.Mohammad Asaduzzaman says:

    Excellent
     

  • Student Dr D says:

    Could you elaborate on why you would not send this patient to cath? This article, which is part of ACEP’s 2013 LLSA Articles, argues that LMCO would validate sending this patient to cath:

    Rokos IC, French WJ, et al. Appropriate Cardiac Cath Lab Activation: Optimizing electrocardiogram interpretation and clinical decision-making for acute ST-elevation myocardial infarction. Am Heart J. 2010;160:995-1003.

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