Saturday, October 21, 2017

30-something with chest pain, a fragmented QRS, and ST Elevation.

A young man presented with acute chest pain.  He had no cardiac history.  He had no medical history at all.  His vital signs were normal.

Here was his first ED ECG:
What do you think?





Here is an old one, from 2 months prior:
What do you think?








Here I will show them again, with comment:
This is very abnormal.
There are deep QS-waves in V1-V3.  QR-waves in V4 and I, aVL
There is a fragmented QRS in V3, which is all but diagnostic of old infarction
There is ST depression in II, III, aVF.

This looks like a very large old MI, but it also looks acute, as the T-waves are tall, too tall to assume this is LV aneurysm (persistent STE after old MI; see this post).
If the T/QRS ratio in any of leads V1-V4 is greater than 0.36 (let's say 0.33 for both convenience and for better sensitivity), then assume there is an acute component to the MI.

Here, in V2, the T/QRS ratio = T/S ratio = 7/15 = 0.48

Furthermore, the ST depression in II, III, and aVF strongly suggests acute MI.


The previous is here:
This one had less STE in V1 and a less tall T-wave in V1.
This one did not have ST depression in lead II, III, aVF

These confirm that today the patient is having an acute MI.

There was a fragmented QRS in V4, III, and aVF and a Q-wave in V5.  The fragmented QRS on the old ECG doubly confirms old MI.

The ECGs suggest new ischemia superimposed on old anterolateral MI.

But this patient has no history of MI or anything else!

I performed this bedside echo (only parasternal short axis is shown):

This shows a clear anterior wall motion abnormality. This does not prove that the MI is acute, but in a patient with no prior history, it must be assumed that it is acute until proven otherwise.


We activated the cath lab.

Coronary angiogram was performed and revealed severe 3-vessel CAD with presumably chronic, old occlusions: mid LAD occlusion, mid circumflex occlusion, OM1 90% stenosis, distal RCA 70% stenosis.  

There was no definite culprit to open and stent.  CABG was planned.

Formal echo revealed moderate LV dysfunction (EF 37%) and multiple regional WMA with elevated filling pressures.  

The initial trop returned at 0.058 ng/mL.

Here is the troponin profile:
So there was indeed acute on chronic MI

It was thought that this was ACS on chronic CAD, with a new insult involving OM or distal RCA.

Here is the next AM ECG:
T-waves are still tall, but the inferior ST depression is resolved.
Fragmented QRS is defined as:
The RSR′ pattern includes various morphologies of the QRS interval (QRS duration less than 120 ms) with or without the Q wave. It was defined by the presence of an additional R wave (R′) or notching in the nadir of the S wave, or the presence of 2 or more R′-waves (fragmentation) in 2 contiguous leads, corresponding to a major coronary artery territory.(1) 

Functional MRI confirmed:
1) decreased LV function, with calculated ejection fraction of 29%.
2)  large, old, non-viable MI in:
      a) the mid to distal anteroseptal and apical area, with wall thinning (aneurysm), consistent with chronic myocardial infarction in the distal LAD territory, and 
      b) the circumflex territory, with absence of viability, old infarct
3) basal inferolateral wall with preserved wall thickness, compatible with acute myocardial infarction. 
4) The RCA distribution showed no old infarct and viable myocardium.

So this MRI helps to determine if there is myocardium that will recover its contractility with revascularization.  Unfortunately, a large part of the heart is chronically infarcted and, in fact, aneurysmal, and will not recover.



Learning Points:

1. Young people do get acute MI and can even have severe coronary disease.

2. If there is clear old MI on the ECG, especially QS-waves, then look at the size of the T-wave.  If it is proportionally large, then it is due to acute MI, or to acute MI superimposed on old MI.  The best measure of proportionally large is a T/QRS ratio is greater than 0.33 in any of leads V1-V4. 

3. The fragmented QRS on a 12-lead ECG is a marker of a prior MI, defined by regional perfusion abnormalities, which has a substantially higher sensitivity and negative predictive value compared with the Q wave.(1)

References

1.  Mithilesh K. DasBilal KhanSony JacobAwaneesh KumarJo Mahenthiran.   
Significance of a Fragmented QRS Complex Versus a Q-wave in Patients with 
Coronary Artery Disease.  



2.  Smith SW. T/QRS Amplitude Best Distinguishes Acute Anterior MI from Anterior Left Ventricular Aneurysm. American Journal of Emergency Medicine 2005; 23(3):279-287. 

 

4.  Kim RJ, Wu E, Rafael A, Chen EL, Parker MA, Simonetti O, Klocke FJ, Bonow RO, Judd RM.  The use of contrast-enhanced magnetic resonance imaging to identify reversible myocardial dysfunction.  N Engl J Med 2000;343(20):1445.


















6 comments:

  1. very cool indeed, Stephen. i am sorry (and embarrassed) to say i never heard of the fragmented QRS sign for prior MI, nor the T/QRS amplitude tool.
    thank you, again,
    tom

    ReplyDelete
    Replies
    1. Tom,
      Very few have heard of either. You're not alone.
      Steve

      Delete
  2. A fantastic and instructive case in every aspects!

    ReplyDelete
  3. Hi Steve,

    Cool case. Is fragmented QRS also means IVCD. I mean, is it the same?

    ReplyDelete
  4. No, not the same! IVCD is usually not due to infarction, fragmented QRS is due to infarction and does not necessarily cause a prolonged QRS duration.

    ReplyDelete

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