I came to work one day and one of my partners said, "Hey, Steve, we had a STEMI this afternoon!"
I said, "Cool, can I see the ECG?'
Of course he said: "Yes, it was a 60 year old diabetic with Chest pain."
So he showed me the ECG recorded in triage:
"That is not a STEMI. That is Arterial Pulse Tapping Artifact (APTA)."
He said: "What? What the heck is that? How do you know?"
1. "Look how bizarre it is."
2. "When bizarre, look at leads I, II, and III. If one of them does not look bizarre, while all other 11 leads do look bizarre, then it is APTA.
A good explanation can be found here: Are these Hyperacute T-waves?
So I explained APTA to him. That the left leg electrode must have been placed over an artery.
They had activated the cath lab and the interventionalist did not notice that it was not a STEMI/OMI.
Then he said: "No wonder the next EKG we recorded just before she left for the cath lab was normal."
Here it is:
So we looked for the followup:
---Cath lab was activated per protocol and coronary angiogram found no angiographic significant obstructive disease in the LAD, LCX, and RCA.
---All troponins were undetectable
I sent this case to the Queen of Hearts PM Cardio app AI system, and she immediately recognized that this was not OMI.
Ken Grauer gives a thorough explanation here:
MY Comment, by KEN GRAUER, MD (9/15/2023):
- As per Dr. Smith — I review in detail the mathematical relationships seen when there is APTA in one of the extremities in My Comment in the January 17, 2023 post of Dr. Smith's ECG Blog.
- Awareness of the mathematical relationships discussed in this Jan. 17, 2023 post — allows you within seconds to recognize with certainty that the unusual deflections in the ECG in front of you is the result of APTA. This is wonderfully illustrated in today's case.
|Figure-1: I’ve labeled the initial tracing in today’s case.|
- As per my discussion in the January 17, 2023 post, when there is APTA — maximal artifact will be seen in the other 2 standard limb leads ( = leads II and III) — as well as in that augmented lead that is common to both of these maximal artifactual limb leads (in this case lead aVF — with these 3 leads showing maximal artifact being within the BLUE rectangles).
- NOTE: It is that augmented lead that shows maximal artifact — that identifies the "culprit" extremity (ie, the Left Foot in today's case).
- The other 2 augmented leads ( = leads aVR and aVL — within the GREEN rectangles) — show approximately half the amount of artifact, compared to maximal artifact leads II,III,aVF.
- Final confirmation that the only thing that can produce these mathematical relationships is APTA — is forthcoming from seeing approximately 1/3 the amount of artifact in each of the chest leads (within the YELLOW rectangles).
- In Conclusion: It literally took me no more than seconds to recognize APTA in today's tracing because: i) I saw a normal-looking lead I — despite bizarre deflections elsewhere; — ii) With maximal artifact in leads II,III,aVF — and about half that artifact amount in aVR,aVL; — and, iii) A lesser amount of artifact in each of the chest leads.