Chest pain and acute inferior-posterior-lateral STEMI

EMS is called to the scene of a 58 year old male complaining of chest pain.

  • Past medical history: Dyslipidemia (high cholesterol)
  • Medication: Atorvastatin (Lipitor)

On arrival, the patient is found tripoding in a chair. He is pale, diaphoretic, and appears acutely ill. He is anxious but alert and oriented to person, place, time and event.

  • Onset: Pain started after carrying luggage up stairs 15 minutes prior to EMS arrival.
  • Provoke: Nothing makes the pain better or worse.
  • Quality: Pain is described as “burning”.
  • Radiate: Patient denies radiation of the pain but complains that the BP cuff is hurting his right arm, even when it’s not inflated.
  • Severity: 9/10.
  • Time: No previous episodes.

He admits to mild dyspnea. He is nauseated but has not vomited. No jugular venous distension while sitting upright. No pedal edema.

Vital signs

  • RR: 20
  • HR: 64
  • NIBP: 199/98
  • SpO2: 95% on room air.

Breath sounds are clear bilaterally.

The cardiac monitor is attached.


A 12-lead ECG is acquired.


Due to equipment and/or network problems the ECG is not able to be transmitted over the LIFENET.

What is your impression?


This ECG shows acute inferior-posterior-lateral STEMI. ST-segment elevation is present in leads II, III, aVF, V5, and V6. Reciprocal changes are present in leads I, aVL, V1, and V2.

The patient was placed on oxygen via nasal cannula at 4 LPM.

The AVOID trial (published in 2015) showed that supplemental oxygen for patients with ST-segment elevation myocardial infarction but without hypoxia may increase myocardial injury and was associated with larger infarct size at 6 months.

Have you changed your protocols?

The patient was given 4 baby aspirin. An IV was started and nitroglycerin was administered.

The patient was sent to the cardiac cath lab. It is unknown whether the culprit artery was the right coronary artery (RCA) or circumflex (LCX).


Stub D, Smith K, Bernard S et al. Air Versus Oxygen in ST-Segment-Elevation Myocardial Infarction. Circulation. 2015;131(24):2143-2150. doi:10.1161/circulationaha.114.014494.

Updated 12/12/2015


  • SoCal Medic says:

    Luggage upstairs? Did he just get back from a trip or just cleaning up the house?When you post the blood pressure, is it hypertensive for him?

  • Shaggy says:

    Ok, just quickly glancing at it while at work: normal axis, and obvious inferio-lateral MI, with reciprocal changes seen in I and aVL. But seeing the ST depression in the right precordial leads leads me to believe there is posterior involvement as well. If the patient is hypertensive, I don’t see what I would do differently for this MI than any other usuall MI, even considering the inferior involvement.However, there must be some catch or you would not post it.:)

  • Shaggy beat me to it.So what else is there to it that we aren’t seeing?

  • Bob Jester says:

    I agree with Shaggy’s interpretation of the 12 lead and like this patient for an evolving inferio-lateral wall MI and that there might be some RV involvement. I would work like hell to convince the patient that a PCI capable hospital is a better choice then the local and begin transport that way. Most of our base doc’s will activate the one call system based on our request if we can’t transmit. As far as treatment, the standard oxygen to patient comfort, aspirin to chew and swallow (we use 324 mg), I would hold nitro until I got at least one IV as large a bore as the patients veins would tolerate, preferably two with normal saline hanging at KVO until we dump his pressure with sublingual nitro. At the patients rate I don’t think I’d give any beta blockers, and fentanyl would definitely be on my order request to OLMC (no standing orders for narcs here in the peoples republic of new jersey).

  • Nick G says:

    um yeah looks like an obvious inferior with possible RV involvement.. I thought with posterior V1-4 all leads need to have depression? So does this mean its an evolving posterior or could it be a blockage off one of the marginal/diagonal branches of the right coronary artery? Anyway im a year into this paramedic student buisness so be nice!! Either way i would be extremely careful of nitrates due to the heart rate…hope im in the ball park! Great blog too im addicted!

  • Tom B says:

    Christopher – Actually, he had just arrived for a trip! 🙂 Hilton Head Island is vacation resort. We receive about 2.25 million visitors a year.I don’t know if the pressure was normal for him, but I doubt it! It was in the neighborhood of 188/92.I was home earlier today but I forgot to look at the code summary! Tom

  • Tom B says:

    Shaggy wrote:”[T]here must be some catch or you would not post it.:)”Shaggy! You hurt my feeling.:)Actually, this one’s a horse.Sorry to disappoint you gentlemen! Tom

  • Tom B says:

    Bob – I thought prehospital beta blockers were now out of favor for STEMI patients. Do you have standing orders for that?Unfortunately, the “Code STEMI” was not called for this patient until after the patient’s arrival in the ED (and it was the weekend).There’s no guarantee the “Code STEMI” would have been called, even if the ECG would have been transmitted, but we’re working on it.Tom

  • Tom B says:

    Nick G – Thanks for the positive feedback.Any ST segment depression in the right precordial leads should make you suspicious for posterior involvement, especially when the ST segment depression is downwardly convex as it is here in leads V1 and V2.The posterior descending artery divides off the RCA and supplies the posterior wall of the left ventricle in many patients, so it’s not uncommon to see posterior extension with inferior STEMI.Tom

  • SoCal Medic says:

    Tom, Normal axis, Elevation II, III, aVF, reciprocal changes in I, aVL, poor r wave progression with Depression in V1, V2 and elevation in V6. InferioPosterior Wall MI (possibly lateral, difficult baseline in V5). Oxygen, ASA, Nitro (after IV with careful monitoring of BP), Morphine for pain and obtain V7-V9, obtain V4R as well because III is higher than II for confirmation. Zofran for nausea, transportation to the cath lab. Would also use the capnography and monitor his airway, my thought is he may have thrown a clot because of the trip, he could throw another and affect his respiratory.

  • Bob Jester says:

    Tom Wrote:I thought prehospital beta blockers were now out of favor for STEMI patients. Do you have standing orders for that?Unfortunately, the “Code STEMI” was not called for this patient until after the patient’s arrival in the ED (and it was the weekend).And I replied:Standing orders here in the peoples republic of new jersey are very limited, communication failure protocols are a bit more liberal. Beta blockers are an OLMC option.Any word on how the patient made out?

  • Tom B says:

    Christopher – Very thorough! I hadn’t even considered the possibility that prolonged travel could lead the patient to throw a clot.But then, clots thrown during travel are generally PEs, not STEMIs or strokes, right? That is not my area of expertise! As for placing additional leads (V4R, V7, V8, V9), I’m certainly not against it, but I probably wouldn’t do it, simply because there’s enough information on this 12 lead ECG to implicate the RCA as the culprit artery, and in the setting of inferior STEMI, ST segment depression in the right precordials is all the confirmation I need for posterior involvement.At this point, the STEMI has been identified, and the heart rate, heart rhythm, and physical exam become more important for the “NTG/no-NTG” decision in the setting of possible RV involvement, IMHO.Having said that, there’s nothing wrong with getting used to what these modified leads look like during acute STEMI! Tom

  • Tom B says:

    Bob – Got it! No word on how the patient made out yet.I know he went to the cath lab, and D2B time was probably within 90 minutes, but I’m certain we could have saved him at least 20 minutes of ischemic time had the trigger been pulled on the cath lab at the point of discovery! I’ll find out the D2B/E2B times at the next quarterly STEMI meeting.Tom

  • Ches says:

    This to me is an obvious inferior MI with posterior and RV involvement. I would treat with high flow O2, ASA 324mg PO, morphine for pain, prophylactic zofran for nausea (after R/O pt is not allergic to any of these). And I would definitely perform a right side 12-lead (V4R, V5R, V5R, V6R), because V4R alone only detects RV MI only 70-80% of the time. I know this pt has RV invokvement due to STE greater in lead III than lead II. Also, try telling a cardiologist that performing a R side 12-lead is not important, because it drastically changes the treatment modality ( increasing pre-load and after-load in RV MI as opposed to decreasing these in non- RV MI’s). Also the “fix” in the cath lab is very different w a pt that has RV invilvement. If breath sounds are clear I would give fluids per cardiologists recommendations assessing breath sounds after every 250cc infused.

  • Clinton says:

    Ok, I would be supprised if this gentelman did not have some involvement of the right ventricle, so lets do a V4R to confirm.  Also, I would guess that his DIB was secondary to a little acute pulmonary edema (secondary to RVF) and a little PEEP would benefit this Pt either by CPAP or BiPAP. Additionally, no fluid bolus for this guy. As far as beta blockers, according to AHA, are no longer used prophylacticaly to treat STEMI's.  Definitely no opioids unless you want to intubate this Pt.  But I am sure I am missing something with the right arm thing!!

  • Kyle says:

    This looks rather black and white to me. The only fancy consideration I would give is the BP cuff hurting his arm may indicate actively blocking dvt. I would check the other arm to test the arm pain significance. Mona and diesel (or a bird if far enough from a cath lab to justify it).

  • Kyle says:

    (clarifying, Mona, as each step is tolerated, and preparing for fluid bolus if needed. His BP would have me pushing my normal meds even if right sided involvement, just more carefully depending on v4r)

  • dr hafez al ali says:

    go immediately  to cath lab to have  primary pci if not available to give pt thrombolytic thearpy  as  
    SK OR  TPAs>

  • Hafez al ali says:

     transfer pt  very soon to cath lab to do primary pci .< if not available to give pt thrmbolytic thearpy  
    AS  (SK_TPAs) >

  • Hisham Selim says:

    This is a case of an acute inferoposterior MI he is eligible for primary PCI if he is in a facility where the cath lab team is ready within 90 min. Otherwise the BP should be well controlled the hypertension could probably be related due to severity of chest pain we can give him pet hiding and of course he is definitely eligible for fibrinolysis 

  • Phil Neuwirth says:

    Great conversation! I would also include; anytime you have an inferior wall MI, a right sided EKG should be done immediately, which I think was already mentioned. However, for some reason….it’s an afterthought. Regarding O2, since the AVOID trial came out, hyperoxia has been studied further, and 02 should be titrated to a pulse ox equal to or >93%. Regarding MOAN, morphine was a topic at the critical care conference in Charlotte last month. MS should be taken off hospital formularies for pain control. We used to use it to tx CHF for pre-load reduction and reducing anxiety when applying CPAP. There is no more use for MS; much better drugs available. Actually, one doc said its a great drug to induce vomitimg, lol. Since the patient does not have hx of hypertension, I’m guessing he probably does not have right ventricular involvement. I think he may be having a very bad day with two separate occlusions; RCA and circumflex.

  • Ben says:

    Does the ST elevation in v5-6 suggest the culprit artery is a left circumflex and posterior involvement would mean this patient has left dominant cardiac vasculature?

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