26 year old male with chest pain and acute isolated posterior STEMI

Here’s an interesting case submitted by a faithful reader who wishes to remain anonymous.

EMS is called to a 26 year old male complaining of chest pain.

On arrival patient is found sitting on his living room couch. He appears anxious and acutely ill.

The location of the chest discomfort is in the center of his chest and slightly to the left.

  • Onset: After a “coughing spell” while riding a bike
  • Provoke: Nothing makes the pain better or worse
  • Quality: Difficult to describe but with prompting the patient calls it “pressure”
  • Radiate: Left side of jaw and left arm
  • Severity: 7/10
  • Time: No previous episodes

The patients skin is pink, warm, and moist.

The patient denies shortness of breath. Breath sounds are clear bilaterally. He is nauseated but he has not vomited.

Past medical history: Healthy
Medications: None

Vital signs are assessed.

  • RR: 22
  • HR: 98
  • NIBP: 140/84
  • SpO2: 98% on room air

The cardiac monitor is attached.


A 12-lead ECG is obtained.


Sinus rhythm with a rate of 94 and first degree AV block. There is subtle ST-segment elevation in lead III with reciprocal ST-segment depression in lead aVL. There is also ST-segment depression in leads V1-V4.

The 12-lead ECG was deemed suspicious by the treating paramedic, but STEMI seemed unlikely due to the patient’s age.

A second 12-lead ECG was obtained just prior to arrival at the hospital.


There is slightly less ST-segment elevation in lead III. ST-segment depression in leads V1-V4 is now more pronounced and shows the classic “down-up” pattern of acute posterior STEMI! 

Remember that ischemia does not localize! Therefore, ST-segment depression that is localized to leads V1-V4 is far more likely to represent acute isolated posterior STEMI than “anterior ischemia” which is a misnomer!

You can use modified posterior chest leads V7, V8, and V9 to shore up the diagnosis. Just know that when these leads are negative, it does not rule out an occluded artery!

After consulting cardiology the patient was taken to the cardiac cath lab and had a 100% occluded circumflex artery (LCX).

Remember, young patients can and do experience acute STEMI!

See also

Acute Isolated Posterior STEMI: It’s Not Anterior Ischemia! 

Ischemia Does Not Localize! What Does It Mean?

Beware confusing the diagnosis of acute posterior STEMI by using posterior leads

Updated 03/13/2016


  • beavermedic says:

    Howdy Tom, Interesting EKG! Here is my stab at a DDx:I am thinking an acute pericardial effusion w/ pericarditis because:- acute onset retrosternal chest pain; radiating to left jaw and arm- Pt position of comfort is seated, upright- 12lead shows diffuse ST changes, QRS voltages on the rhythm strip appear to twist slightly (at least a little, in III)- not pericarditis alone as the J points are not elevated on the 12lead*I do not think an acute coronary event because:- Pt appears haemodynamically stable and to be perfusing well- pain is not relieved by rest- no Hx of CAD- Pt <30 yoI do not think a thoracic aortic dissection because:- pain does not radiate to back- normotensive- Pt <30 yo*Also I could not see any PR depression

  • Hillis says:

    Interesting case as usual..The ECG monitor shows prolongation of the PQ intervval followed by sudden loss of the QRS complex and ventricular extrasystole which is very suggestive of 2nd degree AV block type I Wenchebock fenomenon .. The 2nd ecg shows incomplete RBBB with deep ST depression in the anterior leads, i will go for ECG with posterior leads V7-9 to exclude posterior MI .

  • Tom B says:

    beavermedic -I would have been confused by the patient's age also! I must say this is the youngest STEMI patient I've ever heard of in real life (if colleagues I've met through social media count as real life)! :)It's a brave new world we live in. Tom

  • Tom B says:

    Dr. Hillis -I don't see the incomplete RBBB (perhaps you meant LBBB?) but I love your idea about obtaining modified chest leads V7-V9! That would both confirm the diagnosis and prevent unnecessary delays with reperfusion at the receiving hospital! In this case, there were no delays at the receiving hospital thanks to an ED physician who was "on the ball".Tom

  • Christopher says:

    Rhythm strip shows sinus rhythm at 90-100 w/ 1st degree AVB. Doesn't appear to march out, so the dropped QRS could be transient 2AVB (I'm thinking the AV node isn't getting fed!).Q-wave and STE in III, beginning of a Q in aVF. STD V2-V4, progressing to deeper STD V1-V4. Posterior leads would be helpful.I'm not sure if there is an age component to calling a STEMI (I think there is), but I'm seriously considering this to be the real deal.

  • Tom B says:

    Christopher – It was the real deal! 100% occlusion of the LCX.Tom

  • mark says:

    I thought it was interesting that that the first 12-lead showed STD in aVL and I but it had resolved by the second twelve lead. Thats yet another reason why PHECG's are so valuable. I think the depression in v1-4 looked pretty classic for a posterior MI especially with the tall R waves. I think this is a good example of how circumflex occlusion can be very tricky. I think I saw a study recently that showed that only 32% of confirmed LCX occlusions presented with diagnostic ECG changes. Good Case Nable and Brady. The evolution of electrocardiographic changes in ST-segment elevation myocardial infarction American Journal of Emergency Medicine (2009) 27, 734–746

  • Hey Tom, any thoughts on why this young man ending up with such a severe occlusion? Possible family history, high cholesterol or maybe even a history illicit drug use (I'm thinking cocaine specifically)? Also, how'd the Zoll 12-lead interpretation do? (We don't have very many units out here using Zolls so I'm curious.)

  • Anonymous says:

    Hey. Two question : is the "isoelectricline" the same thing as the "baseline"?andDo you messure the st-segment in relation to tp segment or the pr segment ? The AHA recommends pr segment, but i have always been tought tp segment becouse pr segment sometimes is depressed and therefore could give you à false st-elevation. Sry for My bad english and thanks for a greate blog.Best regards from a danish paramedic Thanks for a greate blog.

  • Tom B says:

    Mark -One has to wonder, if the ECG didn't show "diagnositic ECG changes" then how did they confirm the LCX occlusion?Perhaps they simply meant that it didn't meet the arbitrary "1 mm of ST-elevation in 2 or more contiguous leads" criteria" which isn't saying much! But you're absolutely correct in that LCX occlusions are tricky. There are 3 main epicardial coronary arteries in the heart (RCA, LAD, and LCX) so logic would suggest we would see 33% of our acute STEMIs in each of the arteries, but far more are reported in the RCA and LAD.Does that mean that occlusions don't happen in the LCX or does that mean they are "missed" and misreported as NSTEMI? My bet is the latter! Tom

  • Tom B says:

    MIFL – I'll find out how the computerized interpretive statement did! That's an excellent question.The ZOLL monitors use the GE-Marquette 12SL interpretive algorithm (same as the LP12) and I've seen them "catch" acute isolated posterior STEMI before.Click HERE.As for why this young man had a STEMI? I have no idea!Tom

  • Tom B says:

    Anonymous -Thanks for the kind words about my blog! I consider both the PR-segment and the TP-segment when present! Sometimes you have no choice but to use the PR-segment (tachycardias or choppy baseline like course AF).Isoelectric line is the same as baseline in this context! Tom

  • mark says:

    Tom-My impression was that they confirmed MI by other means such as cardiac markers or echocardiography. Then while in the cath lab they found the LCX occlusion. Of the population with angiographically confirmed LCX occlusions they retrospectively looked at their ECG's and found that only 32% had diagnostic changes. I have to claim a little bit of laziness though- I got that stat from a review article. I haven't read the original study so maybe my understanding of the methodology isn't 100% accurate. Just the same I think thats what they were getting at.I agree that the diagnostic criteria are questionable. I think their intent was to find a balance between an excess of false positives and missing subtle true positives. I think they went somewhat conservative of their value .

  • Tom B says:

    mark – If you ever come across a 12-lead ECG that looks perfectly normal in the right precordial leads (V1-V3) but shows acute STEMI in modified chest leads V7-V9, I'd like to see it! I've heard it can happen, but I have yet to see the evidence in any peer reviewed article or textbook! Tom

  • Ed says:

    Just curious if it's known what the medical history is on the parents and if either of them passed away at an early age?? Great case story, thanks…

  • Mark says:

    Tom-That sounds odd too me. Can't say that I have ever seen that. To clarify my earlier thought ( in case you were curious) that 32% probability for LCX occlusion to predict diagnostic ECG changes was relative to 84% in LAD occlusion and 92% for RCA occlusion. I probably should have included that initially.

  • saif says:

    thanks for this interesting case…..
    1.prolonged p-R ….1st avB
    2.partial RBBB
    3.std in ant leads..post. STEMI ????
    need post leads v7-v9

  • JOHN SAMUEL says:

    this is sinus rhythm with 1st degree AV block, acute inferio-lateral MI and somatic temors. this is definitely an occlusion of the RCA

  • Karen Lynn Robinson says:

    I had my STEMI on February 22, 2009, at approximately 0100HRS, in the very early, wee hours of the morning, just past midnight.  Prior to my STEMI, I had had 3 different MI's — the first of which occured on September 12, 2000, whwn I was 48 years old.  Today (February 22, 2013), at age 61, I now have quite an extensive cardiac history!  However, I have a really very good cardiology treatment team, "up on the hill", as is commonly said, here, in the Seattle, Washington  USA area!  THANK YOU REALLY SO VERY, VERY MUCH, Seattle (Washington  USA) Fire Dpartment, for ALL OF THE HELP AND PROFESSIONAL ASSISTANCE that you have been to me, over the last 12-plus years or so!!!  I TRULY APPRECIATE YOU — AND RSPECT YOU ALL — REALLY VERY, VERY MUCH!!!!!!!

  • Teko says:

    great blog! great exampes!! thanks a lot!!

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