Cardiology Corner - Unstable Angina - The New Definition

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Scott C., M.D. -

Hi Amal.
Great talk. But does make me wonder what is the significance of the history/ RF in this new (heavily industry directed) era of the hs Troponin assay. Presently - I keep patients who have either - positive hsTNT's, concerning ECG's (ie not just stable LVH but new or ischaemic change), OR Risk factors + concerning history. But most of our cardiologist derived algorithms put all emphasis on hs troponins and ECGs. Are we really at the point of sending home diabetic hypertensive 75 yo's with new onset crushing SSCP if serial trops and ECG are negative?

Arthur W. -

Amal (and others), regarding your emphasis on the patient's with "ischemic ECGs and negative enzymes," how does your thought process or level of concern change if that "bad looking ischemic ECG" is completely unchanged from prior(s)? To be black and white about it, if it's unchanged (and has been worked up in the interim) to you is it still "abnormal" (from an acute, ED perspective)?

Sean G., M.D. -

Thank God!
Literature is finally catching up to rational thought process....I have been doing this for two years, and Scot Weingart(not sure of spelling) had a nice EMRAP discussion where he pointed out he utilized this strategy several months ago. I know Amal u are always concerned about keeping us UTD with what is medico- legally defensible, and sometimes u are simply the "messenger" but this has always been a frustrating issue. Nice talk, thank u very much!

Sean G., M.D. -

Unfortunately the internet(I believe) is killing the value of our hx. Pre internet days I rarely heard someone with pain that radiates to the jaw, or felt like an elephant was sitting on their chest....sadly now a days that is very common and for every 100 of the folks who tell me these things about 1 actually is having a heart attack. I gotta believe pts are feeling something in their chest getting on web MD or google, "heart attack" reading the typical sx then suddenly realizing...."yeah thats exactly what this feels like!" Thats the only way I can splain it! Amal did a lecture a few months back discussing which elements of hx are associated with higher rule radiation to the right arm....don't see that on web MD, so Im not hearing that so much.

Amal M., M.D. -

I think common sense must prevail, and if your Hx is really concerning, you're done. I also find that consultants will often blow off our Hx...until they come and see patient themselves. Keep doing the right thing, which means evaluate the patient and not just the labs.
Great question. I think if the ECG is abnormal, but unchanged, I'm feeling better. But it depends on what abnormality the ECG shows. If, for example, the ECG shows Wellens or an old anterior MI which are unchanged, I'm not feeling so great about that. It means there's probably underlying disease, and now you have to balance that with the new history. On the other hand, if the patient has something like LVH with strain which is unchanged, I feel better about that ECG abnormality. Unfortunately like all things in medicine, it's not black & white. These hsTNs are an attempt to make things B&W but there's still going to be some gray.

Kevin M., MD -

Great discussion.

I do remember the days when Troponin meant something. Now, it's just another piece of data. Maybe I'm setting myself up for a lawsuit, but I send people out all the time with slightly bumped Troponin's if the story is very atypical, there are little or no RF's and the EKG is normal. We usually have them see a cardiologist within 72 hours but still. Things are vastly different from say even 3 years ago.

I guess if everybody is somebody, then nobody is anybody.

David H., M.D. (@BritFltDoc) -

Can you clarify what in your opinion is a "negative EKG" ? A normal EKG is one thing, and I don't think anyone would argue with a need for further evaluation for a person with chest pain and clearly ischemic changes. But so many EKGs have T wave flattening or slight subtle inversion. Historically the literature indicates that "normal" and "nonspecific" EKGs risk stratify differently.

Jennifer M. -

Dr. Mattu,
I have a similar question to David. If you have nonspecific changes on EKG and negative enzymes, how worried should you be about these pts being unstable angina? Also, as you mentioned the medical - legal aspect, would you be protected in that respect if the pt just had nonspecific changes? Thanks for your help. And it was great meeting you when I was at Shock Trauma :)

Amal M., M.D. -

If you work in an environment where you worry about legal matters (i.e. in the US), I'd suggest to you that you probably shouldn't even bother sending TNs in the patient you described (i.e. history atypical, no RFs, normal ECG). If you are sending TNs in patients like this and they are even a little elevated, I think you are at higher risk of losing a lawsuit if there's a bad outcome, than if you never sent them at all. Give it some thought. Greg Henry and others in risk mgmt talk about this frequently as well.

David and Jennifer,
If I see non-specific junk, I try to get an old ECG form comparison, otherwise repeat the ECG in a while to make sure nothing is evolving. Some medicolegal solace here is that a good expert will argue that "non-specific" = "non-diagnostic." That's really, in my opinion, how we should refer to normal & truly non-specific ECGs...just call them all "non-diagnostic." In these patients, you really have to rely on the HPI and TNs (if you sent them).

Beware, however, that what the computer calls "non-specific" is not always truly non-diagnostic. Here's what I mean:
Generally, the ECG machines are programmed to call ST segments "non-specific STs" if there is STE or ST depression of less than 1 mm. That means that a patient can actually be having a full-blown transmural MI but if the ST segments are only 0.9 mm elevated or 0.9 mm depressed, it will be called "non-specific" by your machine. So DO NOT RELY ON YOUR MACHINE. I would suggest that if you actually do visibly see STE or ST depression that is present in 2 contiguous leads, and it is obvious STE or ST depression to the naked eye, it should not be called "non-diagnostic." You need to worry about it. Chances are that if you can see it with the naked eye, it's probably at least 0.5 mm deviated.

T-waves are considered non-specific by your machine if they are less than 1 mm inverted. I do worry a bit when the T waves are clearly inverted by at least 1 mm in 2 contiguous leads. If they are inverted less than that, I agree with the machine in calling them "non-specific" or "non-diagnostic." T-wave abnormalities in general do not correlate well with adverse outcomes, so if they really are non-specific (and NOT WELLENS!), I don't worry much about the Ts.

In a bunch of legal cases I've seen for missed MIs or missed-ACS resulting in death, the ED ECGs were read as "non-specific STs" but when you look back at the ECGs, there's clearly 0.5-0.9 mm of STE or ST depression in at least 2 contiguous leads. That's tough to defend in a case when the lawyer enlarges that on a large screen for a jury. Bottom line is to pay close attention to the ST segments, and don't assume that your computer understands what "non-diagnostic STs" are.

David L. -

I guess the question I have that is still not answered would be, again, how many sets would you need to get? If it is just one, at what hour mark are we satisfied that enough troponin is spilled to be detectable. Right now, a negative troponin at 1-6 or even 8 hours after the chest pain started is not satisfactory to send someone home if they would be considered an "unstable angina" patient.

Ruben G. -


I'm having a hard time clarifying in my head what a point that seems paradoxical. On one hand we are saying that troponins are getting so sensitive that they are going to be positive on everyone and not necessarily mean ACS. On the other hand the talk emphasizes scrutinizing the EKG and worrying about an ischemic looking EKG even if troponins are negative. So, the question I'm struggling with is why would a patient with an ischemic looking EKG have negative troponins if his EKG truly represents an ischemic event? If we are saying that troponins are elevated in everyone and so truly sensitive, then why not in the patient we believe to have ischemia by their EKG? Especially serial troponins and serial unchanged EKGs.

Thanks in advance.

Benjamin E. -


What is your opinion on the ASPECT trial (normal EKG, TIMI zero, can send 2h trop/MB and DC home for outpt f/u)? Moreso, what is your timeframe for serial trops? 4h is a long while and I'd preferentially admit to obs, but 2h is a much easier pill to swallow (though I only do the 2h if they qualify per ASPECT). Is this practice medicolegally sound or am I playing russian roulette?


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