37 year old male CC: "Light-headedness"

I received an excellent question this week from a reader who chooses to remain anonymous.

Before we get to his question (and my answer) let’s take a look at the case that prompted the question.

EMS is called to the residence of a 37 year old male c/o “light-headedness”.

Upon EMS arrival the patient is found lying supine on a bench. He is still “light-headed”, appears diaphoretic and also complains of “chills”.

Editor’s side-note: I hope this would be enough for anyone reading this to perform a 12-lead ECG, regardless of the medical history.

The patient denies shortness of breath or chest pain/discomfort.

The patient admits to some nausea but has not vomited.

No feelings of arm heaviness or tingling.

Past medical history is significant for MI x2 years ago which required a stent being placed.

Disturbingly, the patient reports that today’s symptoms remind him of the symptoms he experienced 2 years prior.

Vital signs are assessed.

RR: 20
HR: 92 R
BP: 162/88
SpO2: 100 RA

Breath sounds are clear bilaterally.

A 12-lead ECG is captured.

A second 12-lead ECG is captured en route to the hospital.

What is your impression?

See also:

37 year old male CC: “Light-headedness” – DISCUSSION


  • Rob says:

    NSR/1ST degree HB with T wave inversion in several leads indicating possible ischemia.

  • Brian H. says:

    Faretheewell, right coronary stent. It was fun while you lasted, but now the inferior ST elevation with high lateral reciprocal changes indicates to me that your time is done. Also, 1st degree AV block at the least, I am not going to caliper out my monitor screen but I don’t *think* those t-waves are hiding a 2:1 AV block.

  • Chris says:

    I think with the ST elevation in lead III and aVF with the reciprocal ST depression in aVL lead me to believe that an inferior MI. I also note that there is t wave inversion in leads III and aVF also indicate ischemia or could be left over from past MI but i am still learning as always the 12 lead interpretation. So how far am i off Tom?

  • Mike Sherriff says:

    One would also want to consider a PE with the S1Q3T3. It’s lacking some of the more convincing features such as complete or incomplete RBBB, and inverted T waves in the right precordials, but it’s worth considering. Also it too is consistent with the complaints.

  • Christopher says:

    Pathological Q’s III/aVF w/ T-inversion w/ borderline STE, also borderline STD I/aVL. Only noticable difference between the two 12L’s is a rate change (slower), perhaps they have calmed the pt down.

    I’m considering re-occlusion of a stent or a new occlusion.

  • Dave B says:

    question… if measuring from the “t-p” segment, there does not seem to be STE in the inferior leads.. that is the recommended measuring segment according to AHA and the cardiologist at my hospital. there have been more than one occasion that a difference in interpretation arose based on using the “t-p” segment vs using the “p-r”. feedback on this welcome!

  • Tom B says:

    Interesting comments so far!

    Initially I was focusing on whether or not the inferior Q-waves and inverted T-waves were “old or new” but in light of Brian and Christopher’s comments I went back and examined the first ECG more carefully.

    Now I see flat ST-segments in the high lateral leads (I, aVL) and leads V2 and V3. Do these findings “match” inferior STEMI? Yes. So I can see where this ECG could show early re-occlusion of a RCA stent.

    Of note, the changes disappear by the second ECG.


  • Tom B says:

    Dave B. –

    That’s true. The correct baseline is the TP-segment (when available) although computerized interpretive algorithms tend to use the PR-segment.

    Just remember that the ACC/AHA STEMI criteria are problematic. See my previous post: “The problem of ST-segment elevation”.



  • Tom B says:

    Mike –

    Remember the most common ECG abnormality associated with PE is sinus tachycardia!


  • harrison says:

    It appears we have a rhythm sinus in nature, with a 1st degree AV block. There is prominent T wave inversion in the inferior leads. Ischemia is present. No significant ST changes, and I noticed slight flattening of the T waves on the second ECG as compared to the first.

    Now I did notice the “S1Q3T3 phenomenon” only after it was brought to attention from the comments. However, there is a problem of significance. The patient did have not only one, but two previous IWMI’s…I would bet money that Q waves indicative of such would be present in a resting, asymptomatic ECG. Would that throw the S1Q3T3 out the window? Or just the Q3 part? I am not sure of the answer to this, but imagine the S1Q3T3 tool is rendered useless because of the history. If someone could answer this, I would appreciate it because I am very new to the ECG world.

    What would I do? Treat per cardiac emergency protocols M.O.N.A. (PRN) and transport

  • RM says:

    I agree that the main question here is if the T wave inversion is significant or not with the presence of q waves and a historical MI.

    Without a prior 12 lead to compare to, and with this individuals clinical presentation I would err on the side of caution and treat it as significant. If you were not concerned about an ACS and for some strange reason had this pop up on a 12 lead you did for no reason, I might not be so concerned.

    It is comforting that there are no major changes in the second ecg (although T waves in III look like they might be deepening), however the presentation and the reported similarity in symptoms to prior MI creates a high pre-ecg suspicion for ACS and the combined picture would certainly hint towards re occlusion and/or ischemia.

  • Hillis says:

    I didn’t get the point TOM !!!

    I think his old ECG is necessary to compare it with this one !!

    The ECG shows Q wave which means established necrosis, means that the area is deprived from blood supply , so how could new ischemia develop if already the area is necrotised !!!!

  • harrison says:

    Thats why I believe the S1Q3T3 idea is rendered useless in this case Hillis.

    This guy needs radiology and diagnostic equipment that we don’t have. This guy needs an ER.

  • Terry says:

    True there is the EKG changes that fit the criteria for PE S1Q3T3 but the hx and pt presentation is not there. As Tom said too the pt is not tachycardic. I have seen massive and submassive PEs. The massive ones don’t go well for the pt and they usually don’t make it. With a PE the EKG changes are basically a left axis shift as the heart is straining to push against a saddle embolism. I think the pt is having another inferior wall MI and the qwaves are probably from his old MI.

  • Patrick F. says:

    Looks like ST elevation inferior leads. Question of what the past ECG looks like after past MI is this base line for the Patient or not would work the patient as if it was possibly a new blockage. Fluid bolus ASA. If the patient states symptoms are the same as the last MI makes the HPI of pt to be cardiac.

  • Troy says:

    Ok. I dont see the any ST segment changes that i would classify as STEMI. I do see the Q waves and inverted T waves with your typical PE changes. I would not diagnose a STEMI off this. You can clearly see that It appears that there is a mild STEMI but take in account the movement of the baseline. Just doesnt fit well enough for me to call it on that strip. My question is this….Did anyone look at the RIGHT side of the heart? Maybe your VR leads? Also how was the patient posed when the 12 lead was taken and also were the limb leads placed on the limbs when running the 12 lead? Dont get me wrong i would treat this guy like any other CP patient and give him the full work up. What was his temp?

  • Tom B says:

    Look at all the great comments I miss when I’m gone for 24 hours! Thanks, everyone!

    Rather than respond individually I have created a new post for the discussion.



  • Steve Smith says:

    I see deepening T inversion in III,  and resolving ST depression in V2 and V3.  I would say this is a reperfusing MI or unstable angina.  I can't find where the outcome is????

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