This is the discussion for the case study: 37 year old male CC: “Light-headedness” (posted earlier this week).
Here’s the question asked by the paramedic who submitted the case.
“The first 12 lead ECG shows Q-waves in the inferior leads. Perhaps this isn’t a surprise considering the patient’s history of MI. But what about the flipped T-waves? Do prior MIs flip the T-waves at all?”
Answer: Yes.
Consider the following graphic.
Granted, the patient states his MI was 2 years ago, but in my experience the T-wave does not always recover.
Now I’d like to address those of you who are questioning why Brian H. et al. suspect the possibility that a stent in the RCA is re-occluded. I have to admit, I didn’t see these very subtle findings until they were brought to my attention. That’s probably because I focused on the question that was asked.
Speaking of which, has anyone read The Invisible Gorilla?
Before I go further, I am not saying this ECG shows a STEMI. I’m saying this ECG is very suspicious.
Take a look at the following graphics.
Once again I will invoke Tomas Garcia MD’s rule to “consider the company” any ECG abnormality keeps.
If we accept the possibility that the Q-waves and inverted T-waves in the inferior leads are this patient’s “normal” baseline then we need to amend our approach slightly.
You can see that the ST-segments and T-waves in lead aVL are “pulled down” (flat ST-segments and smaller T-waves) at 21:31:30.
Whenever I see flat T-waves in the high lateral leads I get suspicious! This is often the earliest indication of acute inferior STEMI. The reciprocal changes usually come first according to computer modeling and my own anecdotal experience.
By 21:49:05 this finding disappears. One has to wonder if this is due to oxygen and nitroglycerin!
I realize that no one is disputing this patient is most likely experiencing ACS. The question on the table is whether or not this could be an early STEMI.
Let’s move on to lead III.
These ST-segments are also flattening at 21:31:30, but they appear to be “flattening” in the wrong direction! I say this because the depth of the T-wave is less. In other words, this could be early pseudo-normalization of a baseline inverted T-wave.
What does that mean? It means that if your baseline T-wave is inverted, acute STEMI can “recover” the T-wave prior to ST-segment elevation. That’s why this finding is suspicious.
The finding disappears by 21:49:05.
It’s the reciprocal nature of the changes viewed in leads III and aVL that is troubling!
Finally, let’s look at the right precordial leads V2 and V3.
You can see that the ST-segments are depressed at 21:31:30 and back to normal by 21:49:05. Again, this is troubling because ST-depression in the high lateral leads and the right precordial leads frequently accompanies acute inferior STEMI.
Would an “old” ECG help for comparison? Without question!
The paramedic who submitted the case is attempting to follow up on the case. I’m sure you’d all be interested in the final diagnosis.
Follow the Prehospital 12-Lead ECG blog