Acute Anterior STEMI or Left Ventricular Aneurysm?

EMS is called to a local medical clinic to transport an 81 year old male to the emergency department.

The patient had experienced an episode of chest discomfort the day prior that was accompanied by palpitations and tachycardia.

He described the pain as a “pressure” in the center of his chest without radiation that resolved on its own after he sat down in a chair.

His primary care physician is concerned about “changes on his ECG.”

Past medical history: HTN, asthma, atrial fibrillation, cardiac stents

Medications: Albuterol, aspirin, warfarin, loratadine, avodart, furosemide, diltiazem, flunisolide

Vital signs

  • RR: 20
  • HR: 130
  • NIBP: 142/80
  • SpO2: 97% on room air

Skin: Pink, warm and dry

Breath sounds are clear bilaterally.

At the time of EMS evaluation he has no complaints.

The cardiac monitor is attached.

2010_01_10_Awmm

A 12-lead ECG is captured (which is similar to the 12-lead ECG taken at the doctor’s office).

2010_01_10_Bwmm

Stephen Smith, M.D. of Dr. Smith’s ECG Blog has a decision rule to help distinguish LVA from acute anterior STEMI by looking at the T/QRS ratio in leads V1-V4.

A high T/QRS ratio indicates acute STEMI. A low T/QRS ratio indicates LVA.

To come up with the T/QRS ratio you measure the amplitude of the T wave and divide by the depth of the S-wave.

If there is one lead in V1-V4 with a T/QRS ratio > 0.36, then STEMI is likely.

Or, if the sum of the T-waves in V1-V4 divided by the sum of the S-waves in V1-V4 > 0.22, then STEMI is likely.

Let’s look at the current case.

Slide1

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Lead V4 shows a T/QRS ratio of 0.38 which is suggestive of acute STEMI.

Let’s try the more complicated calculation (TV1+TV2+TV3+TV4 divided by SV1+SV2+SV3+SV4).

1+1.5+6+5 = 13.5

11+13+18+13 = 55

13.5/55 = 0.24 (T/QRS ratio)

Remember, the cut-off is 0.22 so this is very close but favors acute STEMI.

Finally, let’s consider another of Dr. Smith’s ECG interpretation tips: the rule of proportionality.

Lead V5 in this case shows a little bit of ST-elevation but the QRS complex is small. Let’s consider the ST/QRS ratio in this lead.

Slide5

Here we use PowerPoint to “stretch” the QRS complex while preserving the ST/QRS ratio.

Another finding that supports acute STEMI is the well formed R-waves in leads V3 and V4.

Typically LVA shows QS-complexes in leads V1-V4.

Diagnosis: Acute anterior STEMI (confirmed with angiography)

Reference

T/QRS ratio best distinguishes ventricular aneurysm from anterior myocardial infarction. Am J of Emerg Med 2005 May; 23(3):279-287.

Further Reading

Is this STEMI? No, it’s one of the most common reasons for false positive cath lab activation

16 Comments

  • VinceD says:

    I’m going with LV aneurysm, but an echo will be required to determine if there is actually an anatomical aneurysm or if this is just persistent ST-elevation after an anterior MI. Although the ECG has the appearance of a STEMI, looking at the patient I wouldn’t call an alert as he has been asymptomatic for a day. The fact that there are no Q-waves in V3-V5, the leads that exhibit ST-elevation, is a bit unusual based on my understanding of LVA, but I don’t think it rules out the diagnosis.

    I’d probably get med control on the line just to ensure they agree with my course, and will give 324mg of aspirin and O2, but nothing else.

  • HousePA-C says:

    The second EKG shows an irregular rhythm obvious injury pattern consistent with a septal wall MI. The first EKG only shows an irregular rhythm but is only a three lead EKG. I doubt LV aneurysm unless your name is Gregory House. You would need at least a six week history of elevated ST segments in V1 and V2 and a previous MI for that diagnosis. Treat him with everything ya got in that med bag and do a 12 lead…I’ll be in the lounge if ya’ll need me.

  • Brian Terzian says:

    Well it certainly walks like a duck… I agree that in the absence of any acute sxs I would be hesitant to call an alert (actually, in my system, an alert is contraindiciated in the absence of acute sxs). I would perform posterior leads to assess for reciprocal changes. I theorize that if this is acute anterior STEMI, reciprocal changes would be seen in posterior leads. If this is LV anyeurism or some other STEMI mimic, I wouldn’t expect to see reciprocal changes.

  • Christopher says:

    AF w/ RVR 100-130, looks like an anterior MI. If the MD’s prior ECG doesn’t show LVA then STEMI.

  • HousePA-C says:

    And you guys didn’t want to call a MI alert….close enough for me.

  • DB says:

    My interpretation is
    1. AF suggested by the irregular pulse and heart rate,absence of definite P wave, regular QRS and past history of AF
    2. ST elevation MI(st segment concave upwards)–involving the septum because of max changes in leads V3 and V4
    3. I would like to do a Cardiac Troponin test and also other biomarkers with a longer half life than Card.T
    4. I would like to do a coronary angiography and then decide the future course of action
    5. Thrombolysis should not be done for 3 reasons a)Pt not symptomatic….presence of symptoms is a criteria for reperfusion b)Minimal benefit after 6 hrs(max in 2 hrs) c)pt is on WARFARIN
    6. PCI too will have little benefit after 24 hrs but safest to decide further course of action after angiography
    7. Though presence of symptoms is imp. for deciding course of Rx…SILENT MIs can also occur in DIABETICS AND ELDERLY…hence importance of doing TropT

  • VinceD says:

    I was a little unclear in my explanation while rushing yesterday morning. I think the proper nomenclature for what I wanted to describe was “persistent ST-elevation after MI.” A lot of times I’ve heard this called “left ventricular aneurysm,” regardless of whether there is actually an aneurysm of the ventricle. In this case, without an old ECG to compare, or an echo too look for signs of anatomical aneurysm or wall motion abnormality, there’s no way to confirm a diagnosis. Had the patient been symptomatic, it would definitely have been handled as a STEMI, but since he hasn’t had any symptoms for 24 hours, there’s no benefit to rushing or going crazy with prehospital interventions. If he hasn’t had an aspirin, it would be helpful, and the rest can be handled in the emergency department, and if necessary, the inpatient ward.

  • Billy says:

    Normal axis, A-fib RVR, anterior MI with lateral involvement, I see Q-waves > 1mm indicating necrosis and that the anterior MI is fully evolved making sense if symptoms are a day old, however the lateral involvement is new and in hyperacute stage. Looking at this I would say he is still infarcting (lateral)and in the leads its in its low, he has no complaints perhaps a “silent MI” hold off on the STEMI alert but still would go with your chest pain protocols (MONA)

  • Brandon O says:

    Billy, where do you see Q-waves?

  • DitchDoc says:

    I do believe that this man is still having an MI. Dont let the fact that he is not experiencing the symptoms, at the current time, affect the treatment. He experienced chest pains and now has a EKG indicating ischemia. His pulse rate is elevated at 130BPM which I am sure is not his normal resting heart rate. Based on the EKG he most likely has a partial blockage of the LAD that is still perfusing enough of his heart so there is no pain. Also the fact that he is elderly lowers his ability to feel pain.

  • Billy says:

    Brandon, I’m seeing them in V3 and 4, there not huge by any means however they are > 1mm indicating they are pathological.

  • Christopher says:

    Billy,

    The limb leads (I, II, III, aVR, aVL, aVF) appear to be: R, R, R, QS, rs, R.

    The precordials (from V1-V6) appear to be: QS, rS, rS, rS, Rs, R.

    V1 clearly has a Q wave and V2 *may* be QS instead of rS. But V3 and V4 clearly are rS complexes.

  • Mark P says:

    I would say that V2 has a QS complex. I wouldn’t call the barely there squiggle just before the descending limb of the QRS an r wave. In any case he has a Q wave equivalent pattern across his praecordial leads. The r wave in V4 is very small; much smaller than it should be, barring poor lead positioning. AF, if new, is a poor prognostic sign in this context.

  • Tom B says:

    Interesting, Mark! Did you review the follow-up to the case? What do you think of Dr. Smith’s decision rule? Or do you think this was a slam dunk STEMI?

  • Mark P says:

    Honestly I didn’t know that there were calculations/rules that helped distinguish between aneurysm and acute infarction. I’ll read those today – good to learn something new! In general the strongest evidence for aneurysm is the clinical presentation. Elderly man walks into office, ECG performed, raging ST elevation, “I’m as fit as a fiddle doc”. You assume aneurysm in those cases. This case starts with chest pain and other signs of AMI so I’d assume STEMI.

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