Chest pain and transient (subtle) inferior ST-segment elevation

A 45 year old male reports to the fire station complaining of chest pain.

  • Onset: 15 minutes ago
  • Provoke: Nothing makes the pain better or worse
  • Quality: A “heavy pressure” in the center of the chest
  • Radiation: The pain does not radiate
  • Severity: 6/10
  • Time: The patient has been experiencing chest pain on and off for the past few days

The patient is obese, anxious, irritated, rude and difficult. He is evasive about his medical history.

He is placed in the back of the ambulance and undressed from the waist up.

His skin is pale and diaphoretic.

Vital signs are assessed.

  • RR: 20
  • HR: 96
  • NIBP: 128/76
  • SpO2: 99% on room air

The cardiac monitor is attached.


A 12 lead ECG is obtained.


Sinus rhythm with a rate of 94. There is subtle ST-segment elevation in lead III with a downsloping ST-segment in lead aVL. The wandering baseline in lead V2 is unfortunate because it looks like ST-segment depression may be present.

The patient reluctantly agrees to be transported to the emergency department.

When the QRS complexes are small (in this case less than 5 mm) any amount of ST-segment elevation is significant. This is known as the rule of proportionality which states that repolarization is proportional to depolarization.

To fully appreciate this point look at lead III “stretched” while preserving the ST/QRS ratio.

The paramedic in this case provided oxygen, IV access, aspirin, and sublingual nitroglycerin. The patient’s chest pain was almost entirely resolved by arrival at the hospital.


Sinus rhythm with a rate of 87. The 12-lead ECG is now non-diagnostic.

The patient continued to be difficult in the emergency department and eventually signed out AMA.

Of note, the original prehospital 12 lead ECG never made it into the patient’s chart.

Further Reading

Chest Pain and Transient ST-Segment Elevation

59 year old male with chest pain and very subtle acute inferior STEMI

Importance of lead aVL in STEMI recognition

Inferior Hyperacute T-waves

Updated 03/05/2016



  • SoCal Medic says:

    Elevation in III and aVF, reciprocal changes in I, aVL (both Bi-Pashic T Wave). appears to have slight depression in V3 (Bi Pashic T Wave as well), despite poor baseline in V2, willing to bet he has depression with poor R Wave Progression base on his presentation. Skins do not lie, he is anxious, irritated and difficult. Skins plus change in mentation (I am guessing). What are you teaching in you 12 Lead classes to get these "presentations?" lol.

  • Tazambo says:

    As stated above by SoCal Medic.Did you do a V4R as III shows the biggest STE, ? Right side.Also, is there posterior involvement, i.e. V2 and V3 ST depression ?

  • medicblog999 says:

    Man, I've got to get in quicker with these ECGs.As SoCal stated, but putting it all together – inferior MI with Anterior-lateral reciprocal ST depression.SoCal also mentions poor R wave progression, but I don't see that. The transition appears to be in V3, with a gradual increase in the height of the R wave from V1 to V4 (or I may be completely wrong)On a similar note Tom, I would love to learn a little more about the relevance of poor R wave progression and early/late transitions (I.e the clinical significance of the finding). I'm not sure if you have covered it already (I know you have covered R waves etc, but I haven't found anything on what it actually means yet) but if not, do you fancy some homework???

  • SoCal Medic says:

    Medicblog999…R Wave progression can be helpful in the presence of a Posterior Wall MI. Tom, correct me if I explain this wrong, but R Wave progression is typically negative in V1, and Positive in V6, progressing through the V leads. Typically V3 and/or V4 are equal-phasic in that progression. When you see V1 and V2 equal-phasic, along with the ST segment Depression in those leads (like Tom says, consider the company kept), you can suspect the Posterior Wall MI, especially with a suspected Inferior Wall. The baseline in V2 in this example is poor, but with the inverted T in V1, the ST segment depression in V3 with Bi-Phasic T where the R Wave is taller than what one would expect with R Wave progression, I suspect that V2 also is poor in progression.

  • Tom B says:

    SoCal Medic -I don't know what I'm teaching to get these presentations! I think it was a coincidence. :)I like your interpretation, except for the part about R-wave progression, which I will clarify in my reply to medicblog999.Tom

  • Tom B says:

    Tazambo – This actually wasn't my call, although I was there when the patient showed up at the fire station.To my knowledge lead V4R was not captured on the call. I do agree, however, that ST-depression in leads V2 and V3 most likely represents posterior involvement.Tom

  • Tom B says:

    medicblog999 – I did cover R-wave progression and the R/S ratio in lead V1 HERE.In my own anecdotal experience (for example, the previous case) an increased R/S ratio in lead V2 often suggests posterior involvement as well.Conversely, a loss of R-wave progression often indicates anterior STEMI. For example, Dr. Smith's decision rule to differentiate anterior STEMI from benign early repolarization.So, poor R-wave progression or increased R/S ratio in leads V1 or V2 might be nonspecific in some cases, but it might point to pathology in others. As SoCal Medic mentioned (credit to Tomas Garcia MD) "consider the company" any abnormality keeps.Tom

  • Tom B says:

    SoCal Medic – medicblog999 is correct in that the R-wave should start out very small (or absent) in lead V1 and get gradually taller from V1-to-V2-to-V3-to-V4.It may be difficult to tell with the wandering baseline in lead V2 in this case, but R-wave progression actually looks okay to me.On the other hand, the ST-depression in leads V2 and V3 is definitely abnormal, and taken along with the ST-elevation in lead III is certainly cause for concern!Tom

  • Anonymous says:

    I really would call it a Inferior wall MI, with reciprocal changes seen in the lateral leads. also would have been a great idea if they would have done V4R. Just curious, did the BP drop after the nitro?

  • Tom B says:

    Anonymous – I don't know what the pressure was after the nitroglycerin, but I don't recall the paramedics mentioning anything about a precipitous drop in pressure.Thanks for the comment!Tom

  • TOTWTYTR says:

    Even though the EKG is at the least suggestive of Inferior MI, the relief by NTG and O2, is more suggestive of ischemia. The patient is certainly in the right demographic for ACS and has a "classic" story. You didn't say if this was early in the morning or not. That too would follow the classic pattern.

  • Tom B says:

    TOTWTYTR -The time stamp on the initial rhythm strip is 15:23:01.Tom

  • Chris says:

    Nice. Still new and I know to try and keep it mostly simple. Tom I have been learning lots following this page.
    I have no problem calling lead III STE. The baseline wander really is minimal and the voltage in comparison the the rest of the EKG is also interesting to me. So im going to agree that there is an inferior STEMI here. Now I see significant depressions in anterior leads. SO we must have elevations in the posterior leads. so now i have an Inferior/posterior MI, uh oh thats a lotta heart (? RCA block below point of circumflex??).
    Would I have discussed cathlab options with medical control, yes.
    Now the serial EKG, what a nice change with nitro and ASA. Im thinking the artery is dialated from the medications and when they wear off this man will be working on a widowmaker.

  • Chris says:

    Oh yeah possitive reciprocal changes(I,AvL) for inferior MI with flipped Ts. It was a given in my confirming inferior STEMI 🙂

  • i love it that the guy comes to the fire station but was an asshole nonetheless.

  • tedbohne says:

    IWMI.  axis is wnl.  o2 2 ltrs/NC, IV NS tko with blood draw, NTG perhaps MS.  load and tranport code I.   contact med control.

  • Ann L says:

    Coronary artery spasms causing Prinzmetal’s angina? History of cocaine abuse? Coronary artery spasms can cause transient ST elevations. Still treat the pt as a STEMI alert; they might still get a trip to the cath lab.
    I agree; check for right-sided involvement (especially with an inferior MI) before giving Nitro.
    The ST depression in V1 and V2 could be indicative of a posterior MI, but we don’t change tx if the pt has a posterior MI, so it’s not super relevant to us in the field.

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