# To STEMI or not to STEMI, that is the question...



## EMSrush (Sep 29, 2011)

Got an interesting call today, and wanted some feedback from you guys.

We received a Priority 2 call to an urgent care center for a 40 y/o male, possible STEMI. (Yes, we asked dispatch to repeat our response priority, too.) U/A, Pt was sitting up in bed, no visible distress, smile on his face. In condensed form, the conversation between me and the RN went something like this:

RN: This is a 40 y/o male who was having chest pain during dialysis this morning. EMS brought him in here. He's not having any chest pain right now, we gave him ASA and Nitro. The doctor noticed some changes when he compared an old EKG to the one we did today. [RN holds up a rhythm strip briefly] He has had three MIs in the past. Now, we're sending him over to ABC hospital to rule out a STEMI.
Me: Was there any elevation?
RN: I don't know. I don't think so.
Me: How are his vitals?
RN: BP in the 170's, Pulse in the 60's.
Me: Do you have his 12 Lead?
RN: Yeah, somewhere.
Me: Can I take a look please?
RN: Here.

The hospital's 12 Lead showed elevation in V3, V4, V5. It was about an hour old. I put him on my monitor (BP 175/102, Pulse 65, BPM 16, SpO2 100), and got this:







Next, I did a 12 lead and got this:






To make a long story short, we arrived at the ED and my 12 Lead was shown to the attending. He shrugged and said, "Not a STEMI" and walked away. I was perplexed; there seems to be clear elevation to me. Had I got this Pt as an emergency call, I would have called in a STEMI to the hospital. Can anyone explain to me why the attending said what he did? I realize that there's a few things going on in the 12 lead, but I don't see why the elevation was not significant. Please tell me what you see, and what you don't see. 

Anyone care to take a crack at it? I realize the pics aren't the best, but give it a try anyway.


----------



## Shishkabob (Sep 29, 2011)

I wouldn't have called a STEMI, but would have noted the specific findings.


Only things that can be considered elevation are in III and V3 (and III is pushing it), but as you know, the typical rule is "contiguous leads", of which they are not.  I and aVL have what can be said as depression (or at the very least, inversion), and V2 has T-wave inversion.





Did they not do cardiac enzymes or a 15-lead?


----------



## EMSrush (Sep 29, 2011)

Linuss said:


> Did they not do cardiac enzymes or a 15-lead?



No cardiac enzymes and no 15 lead.


----------



## Shishkabob (Sep 29, 2011)

I would have asked for an enzyme test if they could have, and would have done a 15 myself.



Myself, if I get a patient complaining of symptoms that can be construed as a possible MI, but a 12-lead doesn't show anything, I do a 15.


----------



## MasterIntubator (Sep 29, 2011)

One can not call STEMI based on the limb lead print out because of the frequency response... so that elevation in II, III and AVF are not reliable indicators by any means, and never should be. The difference in the monitoring frequency will cause artifact like that.  That is only a monitoring print out and view on the screen.  

The 12 lead print out kinda remotely shows ST elevation in V3.... but no where else. That could be caused by a wayward V3 lead.  You need changes in 2 more consecutive leads on the 12 lead print out.  

The pt sounds stable and in no distress, if was having a STEMI.... you will know it. 

Good learning stuff!!!


----------



## EMSrush (Sep 29, 2011)

Linuss said:


> I would have asked for an enzyme test if they could have, and would have done a 15 myself.
> 
> 
> 
> Myself, if I get a patient complaining of symptoms that can be construed as a possible MI, but a 12-lead doesn't show anything, I do a 15.



I agree with you about the 15 lead... 
Do you feel that V4 has elevation at all? 

In my system, we are supposed to call in a STEMI if .5mm or more of elevation, OR if machine interprets acute STEMI.


----------



## Shishkabob (Sep 29, 2011)

MasterIntubator said:


> The pt sounds stable and in no distress, if was having a STEMI.... you will know it.



Not necessarily.  I've had people complaining of nothing more than "not feeling right", and I've had others make you think all their limbs were torn off in a farming combine.


----------



## Fish (Sep 29, 2011)

This is not a STEMI,

The leads that have elevation are not contiguos and it has LVH. LVH can mimic elevation, I would have treated him the way you did. But no call on the STEMI.

And remember, those lifepaks are about 60-something percent accurate. Don't look at its interpretation.

On another note, if you are ever on the bubble as to wether this is a STEMI or not. Look for reciprical changes. Now let me ask you, did this one have any?


----------



## 18G (Sep 29, 2011)

I would not have called that a STEMI either. As MasterIntubator said, monitoring mode can show elevation frequently but on 12-lead no elevation. 

I only see elevation in V3. 

I'm curious as to why you made this statement, "Had I got this Pt as an emergency call, I would have called in a STEMI to the hospital". Why does how you received the call determine when you call a STEMI? A patient is a patient. Just curious.


----------



## Fish (Sep 29, 2011)

MasterIntubator said:


> The pt sounds stable and in no distress, if was having a STEMI.... you will know it.
> 
> Good learning stuff!!!



I disagree, Atypical S/S resulting in STEMI diagnosis are very common in Women, Diabetics, the Elderly. That is why we do 12-Leads on so many different Chief Complaints.


----------



## EMSrush (Sep 29, 2011)

18G said:


> I'm curious as to why you made this statement, "Had I got this Pt as an emergency call, I would have called in a STEMI to the hospital". Why does how you received the call determine when you call a STEMI? A patient is a patient. Just curious.



Fair question. I'm still a new paramedic, and I was not lead on this call. I was a bit surprised at the feet dragging and "We're still working on his paperwork" delays that I encountered. I didn't feel like a had a tremendous amount of control over the call due to report already having been called in to the receiving ED, and not being the Pt's caregiver. I'm still trying to develop a balance between trusting my (limited but expanding) knowledge base, and the experience of others.

I ended this call feeling kind of "blah". I'm not even sure why, but I'm suspecting it has to do with my lack of participation and some confusion/uncertainty on my part. That's why I'm here.


----------



## MasterIntubator (Sep 29, 2011)

Guess I should have worded it... "You will most likely know it", leaving it open for those uncommon ones.... as I too have had the "I just don't feel right" calls, and your assessment tells you something bad is going on.

My bad yall...   :sad::sad:


----------



## EMSrush (Sep 29, 2011)

MasterIntubator said:


> Good learning stuff!!!



I definitely agree with you here.


----------



## Shishkabob (Sep 29, 2011)

MasterIntubator said:


> My bad yall...   :sad::sad:



Now go to your room and think about what you did.


----------



## 18G (Sep 29, 2011)

EMSrush said:


> Fair question. I'm still a new paramedic, and I was not lead on this call. I was a bit surprised at the feet dragging and "We're still working on his paperwork" delays that I encountered. I didn't feel like a had a tremendous amount of control over the call due to report already having been called in to the receiving ED, and not being the Pt's caregiver. I'm still trying to develop a balance between trusting my (limited but expanding) knowledge base, and the experience of others.
> 
> I ended this call feeling kind of "blah". I'm not even sure why, but I'm suspecting it has to do with my lack of participation and some confusion/uncertainty on my part. That's why I'm here.



I get MI's too going from a hospital to a cath lab and people seem to be taking their good ol time with paperwork. Not sure what's up with that but its happens.


----------



## MasterIntubator (Sep 29, 2011)

You can always count on the team here to set a person straight when you don't  "paint the picture"------ the complete picture..


----------



## MasterIntubator (Sep 29, 2011)

Linuss said:


> Now go to your room and think about what you did.



:rofl:

Thanks.... needed that.  Been up too long.


----------



## Fish (Sep 29, 2011)

EMSRUSH

Reading 12-Leads are one of the most important things we do, you have to be an expert. Like I said, the monitors are not accurate, and a trained Paramedic is always better.

If you do not already know, research this stuff and look for it on future 12-leads.

Benign Early Repolarization
Left Ventricular Hypertrophy
Bundle Branch Blocks
Pericarditis

All of these can mimic elevation, but are not STEMIs!

As far as Bundle Branch Blocks and Paced Rythms, learn what the Sgcarbosa Criteria is so that you can read 12-leads and diagnose it even if the patient has a wide QRS, don't be one of those Medics who says I wont do a 12-Lead cause he is paced and you can't read a paced 12-lead, or look at it and say oh I see a LBBB can't interpret this 12-Lead now! 12-Leads really are fascinating and are very easy to read once you get the hang of it.

Like I said before, if ever you are on the bubble remember this. Is the elevation contiguos? Are there reciprical Changes?


----------



## Fish (Sep 29, 2011)

MasterIntubator said:


> Guess I should have worded it... "You will most likely know it", leaving it open for those uncommon ones.... as I too have had the "I just don't feel right" calls, and your assessment tells you something bad is going on.
> 
> My bad yall...   :sad::sad:



*Hand slap*


----------



## EMSrush (Sep 29, 2011)

Fish said:


> If you do not already know, research this stuff and look for it on future 12-leads.
> 
> Benign Early Repolarization
> Left Ventricular Hypertrophy
> ...



Thank you for your feedback. I really enjoy cardiology. What is concerning me is that I seem to have a fundamental difference of opinion with you guys about V4 (and I'm sure it's something relatively simple). Can someone please PM me and tell me what I'm missing? (or heck, flog me in public if you prefer...) The senior medic also felt there was elevation in V4... and V2. Not huge elevation, but still elevation.

I am well aware of some of the conditions that can mimic elevation. However, I'm not sure that it is good practice for me to pick and choose which ST elevations I treat as a confirmed STEMI and which I do not, with the exception of clear cut issues, such as a LBBB. It is, however, good information to keep in the back of your mind.

I agree with you on the contiguous leads, but NOT on reciprocal changes. There are not always reciprocal changes present, and reciprocal changes should not be relied upon when interpreting elevation.

Furthermore, I don't dx anything off a rhythm strip, other than... rhythm. A 12 lead always follows.


----------



## Fish (Sep 29, 2011)

EMSrush said:


> I am well aware of some of the conditions that can mimic elevation. However, I'm not sure that it is good practice for me to pick and choose which ST elevations I treat as a confirmed STEMI and which I do not, with the exception of clear cut issues, such as a LBBB. It is, however, good information to keep in the back of your mind.
> 
> I agree with you on the contiguous leads, but NOT on reciprocal changes. There are not always reciprocal changes present, and reciprocal changes should not be relied upon when interpreting elevation.QUOTE]
> 
> ...


----------



## medicsb (Sep 29, 2011)

I don't see any STE in V4, but there are only 2 ST segments to look at and they both appear to have some artifact.

The 12 lead is a pretty classic example of LVH w/ strain pattern, I'd file it away as a teaching point for a rainy day.


----------



## EMSrush (Sep 30, 2011)

Fish said:


> EMSrush said:
> 
> 
> > 3. As far as the reciprocal changes, what I was implying is. Say you feel like you might be looking at an inferior wall MI(elevation is creepin on 1mm), but you just are not sure. yet you see depression in V3, V4. Then bam, thats the confirmation you were looking for. Agreed there are not always reciprocal, all I was saying is that it adds fuel to your STEMI fire.
> ...


----------



## mikie (Sep 30, 2011)

*Nstemi?*

Unrelated: Spent some time in the cath lab recently (observing).  PCI is truly fascinating sschtuff.  (the last patient of the day was said to be having an AMI NSTEMI; there was a thrombus/occlusion in graft (previous CABG) going to RCA)


kinda related: In the absence of STE, how could you diagnose a NSTEMI? Reciprocal depression (ST depression) in the EKG? Q (patho) & T-wave changes?


----------



## LondonMedic (Sep 30, 2011)

mikie said:


> kinda related: In the absence of STE, how could you diagnose a NSTEMI? Reciprocal depression (ST depression) in the EKG? Q (patho) & T-wave changes?


Troponin.

Non-specific ECG changes in the presence of a history suggestive of cardiac ischemia are highly suggestive of NSTEMI but do not diagnose it.

In order to make the diagnosis, you need a positive cardiac enzyme test - either like Troponin T or Troponin I - and either a history of cardiac type chest pain or ECG changes.

Alternatively you can shoot their corries there and then, but that's rarely practical.


----------



## mikie (Sep 30, 2011)

LondonMedic said:


> Troponin.
> 
> Non-specific ECG changes in the presence of a history suggestive of cardiac ischemia are highly suggestive of NSTEMI but do not diagnose it.
> 
> ...



Thanks!  The pt. I saw did had elevated enzymes in the past 48 hours so I believe that was their concern.


----------



## FL_Medic (Sep 30, 2011)

This is a good case.

ST-elevation in limb leads on a monitor strip is a good thing to note, but never warrants a STEMI Alert.  This is because the monitor is not calibrated the same as when a 12-lead ECG is performed.  12-leads are much more sensitive and accurate.

The 12-Lead ECG does meet criteria for Left Ventricular Hypertrophy.  With LVH, a Left Ventricular Strain Pattern may occur, frequently causing benign ST-elevation in the right precordial leads (V1, V2, V3), and ST-depression in the left precordial leads (V4, V5, V6).  LV-strain can be identified in LVH by the presence of T-wave discordance (The T-wave is deflected opposite the terminal wave of the preceding QRS-complex).  

This 12-lead does show signs of LV-strain, but what is concerning is the morphology of the ST-segment in V3.  It looks like it is beginning to round over to a convex shape.  Convex ST-elevation is always bad.  Also, V1 has T-wave concordance with a near flat ST-segment, not good.  The QTc is nearing the edge of normal limits as well; this could be contributed to the fact that it is a dialysis patient, and renal patients frequently show alterations in QT-interval and T-wave.  

Another thing to note is the morphology in aVL.  The ST-T changes in aVL are consistent with an inferior infarct.  Meaning that aVL is very reciprocal to lead III, which is usually the first inferior lead to show an IWMI.  

The T-waves are asymmetrical, a good thing, leaning on the side of benign changes.  Symmetrical T-waves are never normal, and may be an early sign of an acute MI.

Taking all of these findings into account.  Is it a STEMI Alert?  No, not in my opinion; there isn't ST-elevation in two contiguous leads.  V3 & V4 could be debated, and if they evolved at all or if there were any dynamic changes, i would concede to a different opinion.  Is the patient having an MI?  Maybe.  Take them to a PCI facility, and if you can transmit... let the doc decide.


----------



## FL_Medic (Sep 30, 2011)

Fish said:


> EMSrush said:
> 
> 
> > I am well aware of some of the conditions that can mimic elevation. However, I'm not sure that it is good practice for me to pick and choose which ST elevations I treat as a confirmed STEMI and which I do not, with the exception of clear cut issues, such as a LBBB. It is, however, good information to keep in the back of your mind.
> ...


----------



## AEMT (Sep 30, 2011)

*Well*

Here is my thought... I did not see it on previous posts or maybe I missed.. You had said they gave nitro and Asa.. Come one people why do we do serial 12 leads or 12 leads after interventions.. Because things can change. I was not there so I don't know the whole story , also I am not a paramedic... I would really like to see the 12 lead before they gave the Asa and nitro.... So back to the basics... What happens when we give nitro plus and platelet inhibitor... Well we dilate the coronary arteries from the nitro and make the platelets less sticky with the asa... So what makes me wonder if it was not 100% occluded or if the nitro was able to open it up a little to allow some flow... Also seeing horizontal/ downsloping depression in lateral leads.... I would think this person is not doing to hot... But also again treat the or not the monitor.... It's hard to say without being there but very well maybe having an ami ... Atleast if the doctor says no not a stemi ... Ask hey just a teaching moment why not??? Good docs will give you a quick run down if not busy.... Atleast ours do.. Plus if during talk he found out pt had Asa and nitro when he previously did not know maybe his mind would have changed... 15 lead good idea why not ....


----------



## KellyBracket (Oct 1, 2011)

Dialysis can be considered to be a "stress-test," and apparently your patient did not do so well with his test! Even without an EKG, and even with a negative troponin, further evaluation will be required in this patient. The clear evidence of LVH, i.e. subendocardial ischemia, does not exactly reduce his risk!

That being said, does anyone else think the precordial leads are a bit off? There should be a fairly clear progression of R-wave height as you run from V1 to V6. I suspect that the lead placement is somewhat off, with V2 a bit more lateral than usual.


----------



## the_negro_puppy (Oct 1, 2011)

I am perplexed by the fact that this patient with a Hx of M.I's c/o chest pain (even if resolved) did not have a blood test for cardiac enzymes. Surely the attending would have considered a NSTEMI?


----------



## LondonMedic (Oct 1, 2011)

the_negro_puppy said:


> I am perplexed by the fact that this patient with a Hx of M.I's c/o chest pain (even if resolved) did not have a blood test for cardiac enzymes. Surely the attending would have considered a NSTEMI?


Are we still talking about a dialysis pt? Does dialysis filter troponin, if not, the trop will be high and the reault pretty hard to interpret. The next question might be, what would the diagnosis change? If this pt has had several MIs, they should already be on antiplatelet therapy and if they're on dialysis, they're hardly a candidate for surgery or PCI.


----------



## MSDeltaFlt (Oct 1, 2011)

EMSrush said:


> Got an interesting call today, and wanted some feedback from you guys.
> 
> We received a Priority 2 call to an urgent care center for a 40 y/o male, possible STEMI. (Yes, we asked dispatch to repeat our response priority, too.) U/A, Pt was sitting up in bed, no visible distress, smile on his face. In condensed form, the conversation between me and the RN went something like this:
> 
> ...



Yeah definitely not a STEMI.  V3 isn't even close.  For there to be ST anything it is in reference to the positive or negative deflection of the first wave at the beginning of the same complex relative to the isoelectric line.  V3 has a positive R wave at the same level of the ST segment.  Not a STEMI.

Might be a NSTEMI or at least an ischemic event, but no STEMI and I wouldn't even call that from the field.


----------



## Jon (Oct 3, 2011)

EMSRush,

I would have checked and seen if they had run cardiac markers yet (perhaps they have an iStat?) and I also would have gotten a copy of the OLD 12-lead. Possibly even asking the doc WHAT he saw, so that I can relay it to the ED staff. 

And do a 15-lead next time, too. They are quick, easy, and tell you so much more.


----------



## AEMT (Oct 3, 2011)

*Forgot to mention*

I forgot to mention in my previous post... I really think v2 and v3 are reversed..


----------



## BEorP (Oct 3, 2011)

Fish said:


> This is not a STEMI,
> 
> The leads that have elevation are not contiguos and it has LVH. LVH can mimic elevation, I would have treated him the way you did. But no call on the STEMI.
> 
> ...



Though the sensitivity may be low, the specificity is quite high so if an LP 15 is calling STEMI, it probably is.

Source: http://www.physio-control.com/uploa...ment of Validation and Accuracy 3302436.A.pdf


----------



## MSDeltaFlt (Oct 3, 2011)

BEorP said:


> Though the sensitivity may be low, the specificity is quite high so if an LP 15 is calling STEMI, it probably is.
> 
> Source: http://www.physio-control.com/uploa...ment of Validation and Accuracy 3302436.A.pdf



Never look at the interpretation first.  Try to never look at it all. Nothing is more accurate than a properly trained human brain.  This is not a STEMI.  V2 & V3 do appear to be swapped. Still no joy on STEMI.  No ST elevation. No reciprocal depression.  There are inverted T's,  but they are chronic in nature from previous multivessel disease with intervention as previously stated.

The fine print on the PDF file stated its accuracy assuming normal parameters.  Said pt started out beyond normal parameters.

When in doubt, transmit (if possible) and consult with OLMC.


----------



## boingo (Oct 3, 2011)

Is it just me or does anyone else see the need for a 15 lead EKG?  I understand looking at R sided cx lead in IMI, however looking posteriorly, i.e. V7-V9 seems a bit overkill.  I honestly can't think of a single case where I would see something in those leads that the standard precordial leads would miss.


----------



## MSDeltaFlt (Oct 3, 2011)

boingo said:


> Is it just me or does anyone else see the need for a 15 lead EKG?  I understand looking at R sided cx lead in IMI, however looking posteriorly, i.e. V7-V9 seems a bit overkill.  I honestly can't think of a single case where I would see something in those leads that the standard precordial leads would miss.



If you place your leads properly rarely would a right side or a 15 lead be necessary.  IMHO.


----------



## KellyBracket (Oct 3, 2011)

Isolated posterior wall MI s are definitely a small minority of STEMIs, but they are definitely out there, perhaps on the order of 4% of STEMIs. You probably get the information that you "need" form the standard picture, but getting someone else to get on board might require all the other leads for evidence.


----------



## TomB (Oct 4, 2011)

KellyBracket said:


> Isolated posterior wall MI s are definitely a small minority of STEMIs, but they are definitely out there, perhaps on the order of 4% of STEMIs. You probably get the information that you "need" form the standard picture, but getting someone else to get on board might require all the other leads for evidence.



That's true. Without posterior leads showing ST-elevation you may not be able to convince ED personnel that it's a STEMI. On the other hand, ST-depression in the right precordials leads is more likely to represent posterior STEMI than anterior ischemia and in some cases acute isolated posterior STEMI will present with ST-depression in the right precordials but no ST-elevation (or extremely modest ST-elevation) in the posterior leads. When the QRS complexes are small as they often are in leads V7-V9 our threshold for ST-elevation is less but this is often not appreciated.


----------



## ekgpress (Oct 7, 2011)

EMSrush said:


> Got an interesting call today, and wanted some feedback from you guys.
> 
> We received a Priority 2 call to an urgent care center for a 40 y/o male, possible STEMI. (Yes, we asked dispatch to repeat our response priority, too.) U/A, Pt was sitting up in bed, no visible distress, smile on his face. In condensed form, the conversation between me and the RN went something like this:
> 
> ...


If I understand correctly- there was an initial hospital ECG (done an hour earlier) - that showed ST elevation in V3,V4,V5 - and then you repeated the ECG and got the following:






First:
- As stated by others, one cannot used ST elevation on a 1- or 3-lead rhythm strip as definitive for ECG interpretation. One can suspect something is going on (and I agree there is clear ST elevation in leads II,III,aVF on the 3-lead rhythm strip) - and this should clearly prompt doing a 12-lead tracing - but one can't "call it" until you see STEMI on a true 12-lead. Note in the rhythm strip that the QRS is predominantly negative (a bit unusual for what one expects in the inferior leads - though totally consistent with the Left Anterior HemiBlock)- and the shape of the ST elevation is concave up in III,aVF as opposed to convex down which is more characteristic of STEMI - so certainly the ST elevation on rhythm strip is of concern - but in no way definitive.

The 12 lead I see is problematic. Note V2 is totally "out of place" (qR, T inverted) - so there is LEAD MISPLACEMENT of lead V2, and this tracing needs to be repeated ...  Otherwise - I don't see acute STEMI - but on the other hand I'm not at all sure that something might not be in process ... Would REALLY help to compare this tracing with the one from 1 hour ago ....  On this Sept 11 (12:48:17) tracing I see NSR; normal intervals; LAD consistent with LAHB; LVH and strain and/or ischemia; the V2 lead misplacement; q waves in I,aVL that could be normal septal q waves OR could possibly be related to infarct of uncertain age (q in aVL a tad bigger than usual for septal q waves ... ); RAA (peaked P in II); LAA (deep neg P component in V1); persistent S waves (thru to V6); ST coving with some J point depression in esp. I and also aVL (the ST coving a bit uncharacteristic for "strain"); rSr' in V1 with ST elevation (of itself nothing definitive, as this may be seen with rSr' pattern); nondescript, seemingly concave up ST elevation in V3 - with artifact precluding assessment of V4 - and NO true V2 to determine if what I see on this tracing in V3 is anything of concern or not ....  Clearly depends on the clinical picture - and comparison with prior tracings - but I'd suspect changes on this tracing are probably old in a patient who clearly has LVH and may or may not have CAD with some ischemia of uncertain age ...  Hope that helps - Ken Grauer, MD


----------



## ekgpress (Oct 12, 2011)

Two points: i) Whether or not there is ST segment deviation is based on the PR segment baseline.  In view of this - the ST segment in lead III is clearly elevated (albeit not by a lot) - and the ST segment in lead aVF is probably also up a tad.  Point ii) More important than "amount" is ST segment "shape" - so that the ST segment in lead II is coved. Thus, there are some changes in each of the inferior leads (II,III,aVF).  That said - I'd guess that these changes are not acute, and are more the "reciprocal" of what we are seeing in leads I,aVL. There is LAHB and LVH, further complicating assessment - but of concern is the ST segment coving particularly in lead I that is usually not seen with pure "strain" from LVH.  There is clearly lead misplacement with lead V2 (that looks totally out of place) - and this complicates assessing what looks to be some coved ST elevation in V3 (albeit with artifact) and with the too-much-artifact-to-tell that we see in lead V4.  In short - definitely not at all diagnostic on this ECG of STEMI - but possibly something is going on - and follow-up tracings, the clinical course, troponins, and comparison with prior tracings would be needed to know for sure.


----------



## Theo (Oct 24, 2011)

Awesome thread and great discussion. This weekend, I had my first patient with ST-elevation from causes other than a MI. It was a great experience (for me) that was a perfect reminder of why we have to stay sharp and understand differential diagnosis. 

60 y/o male, mild shortness of breath, no pain what so ever, no respiratory distress, a bit lightheaded and said he felt "shaky". Vitals were all stable, BP was a bit on the low side. Patient was being transported from a small ED to a facility that could provide definitive care. 

12 Lead revealed ST elevation in V1, V2, II, and III. The strips were cookie cutter ST-elevation, but the guy didn't have any of the corresponding S/S of an MI. 

Patient had no prior heart history, no HTN. He had a history of depression and earlier this year had acute renal failure in which he was on dialysis for only one week and then was cleared. He said they never found the cause of his renal failure. ED nurse said patient was again in acute renal failure and was mildly hyperkalemic. 

I knew about peaked T waves from hyperkalmeia, but didn't see any peaked T waves on the ECG and the patient's strip never changed throughout transport. Perfect examples of ST-elevation (kicking myself for not making a copy to share). Vitals remained stable, no pain at all. 

After the call I did some research and found that in some rare cases, hyperkalemia can produce "pseudoinfarction" patterns on the 12-lead. As the levels of potassium begin to rise, then you will begin to see peaked T waves.


----------



## ekgpress (Nov 7, 2011)

Theo said:


> Awesome thread and great discussion. This weekend, I had my first patient with ST-elevation from causes other than a MI. It was a great experience (for me) that was a perfect reminder of why we have to stay sharp and understand differential diagnosis.
> 
> 60 y/o male, mild shortness of breath, no pain what so ever, no respiratory distress, a bit lightheaded and said he felt "shaky". Vitals were all stable, BP was a bit on the low side. Patient was being transported from a small ED to a facility that could provide definitive care.
> 
> ...


----------------
Sorry for my delay in responding - Yes, a picture is worth a 1,000 words - and a beauty of current cell phones is that they enable reasonable quality photos very easy on-the-scene ... There are a number of causes of T wave peaking not due to infarction - including hyperkalemia & repolarization variants. Usually one can surmise what is going on from "gestalt" of the overall tracing - but hard to say more without a copy of the tracing you saw .... Next time!


----------



## Brandon O (Nov 16, 2011)

MSDeltaFlt said:


> Never look at the interpretation first.  Try to never look at it all. Nothing is more accurate than a properly trained human brain.  This is not a STEMI.  V2 & V3 do appear to be swapped. Still no joy on STEMI.  No ST elevation. No reciprocal depression.  There are inverted T's,  but they are chronic in nature from previous multivessel disease with intervention as previously stated.
> 
> The fine print on the PDF file stated its accuracy assuming normal parameters.  Said pt started out beyond normal parameters.



The Marquette algorithm for STEMI is, as noted, highly specific but not very sensitive. It's true that the specificity depends on various things being in place. However, they're relatively controllable. The big ones are

-- Data quality
-- No tachyarrhythmias (like most humans, it gets confused when the rate is fast)
-- Data quality
-- No notable PR depression (it does use the PR segment to calculate STE, and hence disorders like pericarditis can cause problems)
-- Data quality!

It's not a replacement for a human, but used properly it's a very useful piece of data to add to your overall gestalt when forming a diagnosis. (Mind you this is for calling a STEMI; other interpretations may be more or less accurate.)

Partly due to the above but also because of obvious weirdness (note the R-wave progression), I think the correct response to the given 12-lead is to perform a repeat 12-lead with good quality and work with that instead. Garbage in, garbage out.


----------

