Check out this 12-lead.
What do you think?
Okay, fair enough, you need a story. Let’s say the best story possible: pale, clammy diaphoretic, crushing chest pain of sudden onset, history of coronary artery disease.
What do you do if you are the medic?
Call in a STEMI alert?
Call in a possible STEMI alert?
Don’t call in a STEMI alert, because it is not a STEMI?
I have showed this strip to many doctors and paramedics and the general consensus is it is a nondiagnostic 12-lead (insufficient ST elevation in V1, V2 and V3), and absent a recent 12-lead, they would only send the patient to the cath lab with a really good story.
What was the bottom line?
The hero medic (damn, not me) called it a STEMI and the patient who went to the cath lab based on story, not so much on the 12-Lead, had a 100% occlusion of the LAD.
Look again at the 12-lead. How can you reconcile the 12-lead with the final diagnosis?
If you are a reader of the EMS 12-Lead blog you are likely jumping up and down, waving your arm in the air, trying to get me to call on you. If you have read that blog, you likely have the answer. It is called the law of porportionality.
I read about it recently on the site and it came to mind in the later discussions of this 12-lead.
Here is what Tom Bothhillet, the guru behind the EMS 12-Lead blog, has to say about the law of porportionaility when discussing similar ECGs:
So with that in mind, let’s look at V3 in particular.
Using a powerpoint to stretch the ECG vertically, we get a better sense of the porportion between the QRS and the ST segment.
The ST segment is disporpotionately large compared to the QRS.
This is something valuable to keep in mind, when the QRS is small in leads V2 and V3. You may be able to see an anterior STEMI that others may miss.
This tip and many others are available to readers of the EMS 12-lead blog.
If you really want to improve your 12-lead understanding, EMS 12-Lead is must reading. Bouthillet also offers an excellent web cast called STEMI Recognition: Beyond the Basics, which is available on his site.