Do we need serial ECGs for this case of chest pain?

From Drew Williams

A 40-something patient called 911 for 30 minutes of left sided chest pain radiating to right arm/shoulder (Smith aside: radiation to right shoulder is a really high risk symptom, and especially radiation to both shoulders).  

A prehospital ECG was recorded at 2238.

The Zoll conventional computer interpretation said "nonspecific ST-T abnormalities"

What do you think?

This was sent to me by Drew with no information.  My interpretation was "Acute OMI."  Why?  There are hyperacute T-waves in III and aVF, and reciprocally inverted hyperacute T-wave in aVL.  There is also a flattened ST segment in V2.  So this is OMI affecting the inferior and posterior walls.

Here is the PMCardio Queen of Hearts ECG AI Model:

She sees the inferior OMI but apparently does not see the posterior OMI.  Nevertheless, she recommends "Immediate invasive strategy."

The medics did not activate the cath lab based on this ECG. They did record more serial ECGs:

At 2244 (time 6 minutes after first):

At 2246:

At 2254 (16 min):

At this time, the cath lab was activated.  

Here is the angiogram:

Very tight RCA stenosis, with some flow beyond.  

It was stented.

Learning Point:

Acute OMI can be extremely subtle on the ECG, but still be diagnostic.  The Queen of Hearts can help you see it.

Recording serial ECGs is critical if you don't see the OMI on the first one, and important even if you do.

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MY Comment, by KEN GRAUER, MD (5/2/2025):

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Credit to the EMS team for their excellent work in today's case!

• The EMS team immediately recognized the high-probability risk of today's 40-something year old patient — who presented with new-onset CP (Chest Pain), radiating to his right arm/shoulder.
• The team recognized the abnormal initial ECG that was immediately recorded.
• They appropriately obtained rapid-succession serial ECGs — and successfully enabled cath lab activation with the recording of the 4th ECG.
• End Result: Thanks to the excellent work of the EMS team — the order for cath lab activation was made within 16 minutes of recording the 1st ECG — which is hours sooner than all-too-many cases sent our way for review/discussion in Dr. Smith's ECG Blog.

I focus My Comment on several additional pointers that make for a few recurrent themes that we regularly address on Dr. Smith's ECG Blog.

• By way of illustration in Figure-1 — I have reproduced and placed next-to-each-other 3 of the 4 ECGs in today's case (ECG #3 shown above in Dr. Smith's discussion — was obtained just 2 minutes after ECG #2, and is essentially unchanged from that ECG #2).

Figure-1: Comparison between the 1st, 2nd and 4th ECGs in today's case.

Additional Pointers:

Given the history in today's case of new-onset worrisome CP — ECG #1 by itself (as indicated by Dr. Smith) — is already diagnostic of an acute infero-postero OMI until proven otherwise. Pending receptive physician providers — the cath lab could have been activated at 22:39 (ie, within one minute of seeing ECG #1).

• Although subtle — T waves in each of the inferior leads of ECG #1 are larger and "fatter"-at-their-peak and wider-at-their-base than expected (given relative amplitude of the QRS in each of these respective leads).
• To Emphasize: Recognition that the T waves in these inferior leads of ECG #1 are hyperacute is subtle — BUT — we know it is "real" until proven otherwise because: i) The patient's history is very worrisome; ii) These abnormal T waves are seen in all 3 of the inferior leads; iii) There is reciprocal ST depression in lead aVL (as well as subtle ST segment straightening and slight depression in lead I, which is the other high-lateral limb lead); and, iv) As per the next bullet — leads V2 and V3 indicate associated acute posterior OMI.
• One of my favorite ways to verify that subtle limb lead findings potentially suggestive of acute inferior OMI are "real" — is to focus on leads V2 and V3. Both of these anterior chest leads normally manifest slight, upward-sloping ST elevation. As a result — the BLUE arrows that I've drawn in these leads in this patient with new CP are diagnostic of acute posterior OMI — and that finding confirms the acute inferior OMI that we suspected in the limb leads (because of the usual common blood supply provided by the RCA to these 2 areas).

KEY Point:

Unless comparison of serial tracings is accomplished with both ECGs you are comparing placed next-to-each-other — you will miss subtle-but-important changes!

• Isn't it EASIER to compare ECG #1 and ECG #2 from Figure-1, in which I have placed these tracings next-to-each-other?
• Isn't it EASY to see slight-but-definite increase in the relative size (and volume) of the T waves in each of the inferior leads in ECG #2? (again — relative to QRS amplitude in these leads).
• In addition — the degree of reciprocal ST depression in lead aVL is clearly increased in ECG #2 compared to ECG #1.
• NOTE: If there was any doubt about whether ECG #1 indicated a need for immediate cath — that doubt would have been eliminated by the "dynamic" ST-T wave changes in ECG #2, that have occurred in just 6 minutes since ECG #1 was recorded.

Regarding ECG #4:

The acute inferior MI is now with this 4th serial ECG obvious from across the room (ie, There is increasing ST elevation in leads III and aVF — with the hyperacute T wave in lead III now surpassing R wave amplitude in this lead).

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Learning Points:

• The diagnosis of acute infero-postero OMI in today's case — can be made solely by the history and the initial ECG. While excellent work by the EMS team is accomplished, to document what transpires over the ensuing 16 minutes en route to the hospital — no other ECG is needed to know that prompt cath lab activation is indicated (unless you are faced with having to convince a skeptical cardiologist — in which case, hopefully ECG #2 will be all that is needed).
• Troponins will certainly be drawn. But as we've often emphasized on Dr. Smith's ECG Blog — the initial (and even the 2nd) Troponin may be negative despite acute OMI — so there is nothing that we will learn about the need for prompt cath from these first few Troponin values. (Troponin may give us a "rear-view mirror look" at relative size of the MI).
• BEST use of serial ECGs — is to indicate the presence and relative severity of CP on a scale of 1-to-10 for each serial ECG. As we have often emphasized — correlation of each ECG with the presence and severity of CP at the time each ECG is recorded — may provide invaluable insight as to whether the "culprit" vessel has spontaneously opened or has once again spontaneously closed.
• Today's case provides a wonderful illustration of the phenomenon of "dynamic" ST-T wave changes — that on occasion may serve to remove any doubt that might remain as to whether an acute event is actively ongoing.