A 50-something woman with history of DM and HTN presented with one hour of chest tightness. I was screening all patients at triage and we obtained this ECG:
|The computer read was “Normal ECG”
What do you think?
I was worried about the small amount of ST elevation in inferior leads, with a bit of reciprocal STD in aVL.
There is also T-wave inversion in V2, which is usually a very suspicious sign of early posterior MI. Posterior MI of course is strongly associated with inferior MI. However, the P-wave in V2 is inverted, which tells us that the lead was placed too high and this usually results in false positive T-wave inversion in V2.
So I was not entirely convinced.
A previous ECG was available from a few months prior:
|This also had some inferior STE, but with less STD in aVL
Let’s look at the limb leads side-by-side:
I did not think it diagnostic, but wrote in my triage note:
“ECG equivocal and will need frequent serial ECGs.”
The ED was incredibly busy, with 40 patients waiting in triage for beds (all of whom I had already screened), so we put her in a chair in triage. The wait for a bed was approximately 4 hours.
I went back to screening patients and time flew by and I forgot to get the 15 minute follow up ECG, but then remembered and did get one at about 45 minutes:
|Computer interpretation: “Normal ECG”
What do you think?
My interpretation: This is a clear change and diagnostic of inferior MI.
I activated the cath lab and brought her to the critical care area.
While the cath lab was getting ready, we recorded a right sided ECG:
|V1=V1R which is the same location as V2
V2 = V2R = same location as V1
V3-V6 = V3R – V6R
Inferior MI is obvious
There is no right ventricular MI evident on these ECGs.
Angiogram showed a distal RCA occlusion which was stented.
Echo showed inferior wall motion abnormality.
If in our system we did not interrupt physicians with “normal” ECG, this OMI would have been completely missed, even with 2 ECGs! And she would have waited 4 hours in triage while her myocardium infarcted.
This probably happens frequently. We know that 25% of OMI do not get emergent angiography. Many of them might be sitting in triage.
The computer cannot be trusted when it says “Normal ECG”
The triage physician should see every ECG, but this only helps if the triage physician can recognize MI that the computer does NOT recognize (i.e., many readers of this blog).