90 year old male CC: "Possible stroke" – Conclusion

This is the conclusion to 90 year old male CC: "Possible stroke". You might want to go back and familiarize yourself with the details of the case. Let's take another look at the 12-lead ECG.

Now with the computerized interpretive algorithm.

On Facebook I had asked whether or not this ECG showed signs of ischemia.

This ECG shows ST-depression in the lateral leads (I, aVL, V5 and V6) and modest ST-elevation in the right precordial leads (V1-V3). That's because it shows a strain pattern or secondary repolarization abormality due to left ventricular hypertrophy.

According to at least one study this is the most common cause of ST-elevation in chest pain patients. Hence, it is a very important pattern for paramedics to recognize in the field (although it's rare for LVH with strain to fool the GE-Marquette 12SL interpretive algorithm).

How would we know it's a strain pattern?

When we look at any 12-lead ECG we should consider the Six Step Method (or some other standardized approach).

Here we see that the patient is in sinus rhythm with a normal frontal plane axis. The QRS duration is < 120 ms so it's not a bundle branch block or paced rhythm.

At this point we might pick up on ST-depression in the lateral leads but it's too early to call it ischemia. We need to consider other possible causes. Since left ventricular hypertrophy often presents with ST-depression in the lateral leads that is a likely culprit.

Let's add the depth of the S-wave in lead V2 with the height of the R-wave in lead V5 (or V6 — they're both about the same). Is the result equal or greater than 35 mm?

Yes!

You don't need calipers for this because it doesn't have to be perfect. 35 mm is 7 large blocks so eye-ball it. The S-wave in lead V2 is at least 4 large blocks deep (it's actually more than 5 but this is the "fast and dirty" method) and the R-wave in lead V6 is at least 3 large blocks in amplitude. That's greater than 35 mm so you've met the criteria.

There are other criteria for LVH but this is the most important for ruling out STEMI mimics because LVH is usually an anterior STEMI mimic so the most important issue here is the depth of the S-waves in the right precordial leads (V1-V3). With a "strain pattern" the deeper the S-waves the more pronounced the secondary ST-T abnormality in the opposite direction.

Conversely, the taller the R-waves, the more pronounced the ST-depression and T-wave inversion. A lot of people talk about the shape of the ST-segments and T-waves in the presence of LVH, how it should be asymmetrical and upwardly or downwardly concave. That's ususally true but it's not always the case.

In this case the "strain pattern" is fairly modest. The ST-elevation in V1-V3 is not particularly impressive. Other times the result can be quite profound.

If you're still not clear on what a "strain pattern" is with LVH, take a look at the precordial leads. The QRS complex starts out negative in lead V1 and ends up positive in lead V6. The transition lead is lead V4 (which is equiphastic). As the QRS complex transitions from negative to positive, the T-wave transitions from positive to negative.

That's what we call a "widened QRS/T angle" which means that there is more than 100 degrees difference between the QRS axis and the T-wave axis. Let's take a look at the computerized measurements. The QRS axis is 16 degrees and the T-wave axis is 148 degrees.

To be much simpler about it, with a strain pattern positive QRS complexes have negative T-waves and negative QRS complexes have upright T-waves. (You should not include isoelectric or equiphasic QRS complexes in this analysis).

The general appearance of this 12-lead ECG is one of T-wave discordance. That's a finding that should almost always make you pause and consider that you're dealing with a secondary ST-T abnormality — in other words a STEMI mimic.

This patient received a fairly extensive workup for his near-syncope including a CT scan and nothing was found. He was discharged from the emergency department.

You can find previous posts about left ventricular hypertrophy here.

See also:

The Code STEMI Web Series comes to First Responders Network! 

1 Comment

  • jason says:

    leads I, II and V5 appear to have an upwards “slur” from the pq segment to the initiation of the QRS. Anybody think this is a delta wave and this pt has WPW?

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Comments
know it all parapup
83 Year Old Male: Shortness of Breath
@ Kyle I would question your authority to call out people for not having a license or being a know it all parapup when your tx basically entails "call medical control." I think we can both agree that his cardiac output is not great at all. I assume your reluctance to give him any other…
2014-10-30 20:26:11
Kyle
83 Year Old Male: Shortness of Breath
Well st elevation in avr and v1 associated with anterior and lateral depression would call for possible posterior wall MI. 15 lead would be in order. Also check all the leads for appropriate placing. If v7, v8, and v9 show the elevation i would treat as a STEMI per my protocol. Asprin only until medical…
2014-10-30 18:14:05
Tim
The most awesome STEMI test on the internet!
Thanks for the app. It made me think about all that one may see in the field. The only problem was I never got a score or saw the results of how I did other than saying I had completed the test. Anyway a great way to get the old brain working.
2014-10-30 13:14:27
Brian
83 Year Old Male: Shortness of Breath
I mostly agree with dustin. I believe this is may be an isolated posterior MI. The R wave in V2 points to it being a posterior MI. otherwise it is a 1st degree av block with a LAHB. I am somewhat concerned with the concordant t segment depression noted and in fact if you were…
2014-10-30 04:22:44
Karl Brennan
Understanding Amiodarone
Great article , however in VF caused by hyperkalemia it should be avoided along with lidocaine , Since it shuts down the K channels, the eiteiology of the arrest hyper K, K channels are needed to exchange K in the cell. Calcium , Bicarbonate, dextrose and insulin should be used to decrease K levels along…
2014-10-30 03:04:45

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