st segment monitoring

Specialties CCU

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I'm having a hard time with st segment monitoring. For example if you had a pt with serial troponon levels between 79-89, mbcpk 1.8. The st monitoring shows: avr) 0.9, avl) 0.4, avf) -1.5, I) -0.3, II )-1.6, III )-1.4. Chest leads show: v1) 1.6, v2) 0.8, v3) 0.8, v4) -0.5, v5) -0.7, v6) -0.7. What would this indicate based on the st segment monitoring. How many leads need to be postive (st segment elevation) to be dx as ischemia/MI? How many mm does the elevation need to be to be considered postive? Do you have any good sites for more infor? Thank you.

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Specializes in CCU/CVU/ICU.
I'm having a hard time with st segment monitoring. For example if you had a pt with serial troponon levels between 79-89, mbcpk 1.8. The st monitoring shows: avr) 0.9, avl) 0.4, avf) -1.5, I) -0.3, II )-1.6, III )-1.4. Chest leads show: v1) 1.6, v2) 0.8, v3) 0.8, v4) -0.5, v5) -0.7, v6) -0.7. What would this indicate based on the st segment monitoring. How many leads need to be postive (st segment elevation) to be dx as ischemia/MI? How many mm does the elevation need to be to be considered postive? Do you have any good sites for more infor? Thank you.

The st changes need to be seen in 2 related leads (inferior, lateral, anterior, septal, etc) to be considered significant. You'll find gazillions of info on this stuff with a simple google search.

A big thing to remember is (if possible) to compare with a prior/baseling ecg...as these changes may be chronic for the patient. In the face of inconclusive enzymes, you have to take the patient's symptoms into consideration (is he/she symptomatic at all?). If admitted w/chest pain and nonspecific st-t changes, you have to err on the side of caution...patient needs a work up. You'll find that alot of this stuff is more 'art' than 'text-book' as the ecg is only one (important) component in diagnosing acs/mi. ..but you can find alot of the answers in text-books and internet...

Also..if troponins are really 79-80's...something's obviously happened and patient needs intervention. And keep in mind that troponins can stay elevated for 2 weeks post event...where the other enzymes will fall off more rapidly. So, a patient could look absolutely ok to you 10 days post mi but still have panic troponins come back from lab...

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sorry I meant 0.78 to 0.89 serial troponin. Does that seem significant in light of the st segment elevations that I wrote earlier? And how would one distinguish between if someone had an MI with postive troponin or if some one was still evolving in the injury process? How do you know if the person is still having injury or is trending down? I hope someone can understand the questions-I know I may not make sense. Thanks

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Specializes in CRITICAL CARE.

I also want to know more about st segment elevation. because there is any defined level is given in books for positive or negative in relation to troponin level.

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Specializes in CCU/CVU/ICU.
sorry I meant 0.78 to 0.89 serial troponin. Does that seem significant in light of the st segment elevations that I wrote earlier? And how would one distinguish between if someone had an MI with postive troponin or if some one was still evolving in the injury process? How do you know if the person is still having injury or is trending down? I hope someone can understand the questions-I know I may not make sense. Thanks

Umm.ok. A mild bump in troponin combined w/elevated st-segment is very significant if patient is symptomatic. If patient is not symptomatic it gets a little trickier...as an example, diabetics are notorious for not 'feeling' an mi...so usually further investigation is needed to be certain. Another good example is that renal patients can have a mildly high baseline troponin...so it's not diagnostic in isolation.

If a patient experiences a st-elevation/ami, you'll eventually see significant q-waves develope over (usually) an hour to a few...Think of these q-waves as 'scars' as they usually never go away. This is one way to tell if mi is older (few hours at least)

...And as far as st-elevation, even after intervention (ie PTCA, fibrinolytics, etc) an st-elevation can continue (a poor prognosticator...)

In general, if st elevation persists the MI is continuing to 'evolve' and myocardium is being lost.

And then there're NonQ-Wave MI's that haapne when the infarction is 'smaller' and not transmural (through the entire heart-wall)...in which case although you're losing myocardium you wont see an st-elevation at all. (these are the mi's/ACS that show st-depression and inverted t-waves, etc).

Oh..and another thing about mild st-elevation in an otherwise healthy person/heart..there is a phenomenon called 'early repolarization'...Which, in plain english, means that the t-wave is happening early and causing the st-to appear elevated...though it's not significant.

So.. an example would be a patient with chronic renal insufficiency comes in complaining of chest pain and sweating.. ECG shows non-specific st-changes and a mild bump in troponin...and everyone starts worrying about mi.

Workup reveals GERD, a 'normal' for patient baseline tropoinin elevation, and st-segments that are the same as last months ecg. (no mi, despite the worrisome troponin and ecg)

THis is a basic example, but highlights the fact that diagnosing an MI/ACS/NQWMI with ecg alone can be tricky. YOu'll eventually see that this stuff becomes more 'art' than textbook...and becomes much easier with experience.

LOng story short...think of ecg and troponins as very important 'tools' in your tool-box. They're both very helpful and important in determining AMI diagnosis, but when things get inconclusive/non-specific it gets a wee more difficult and you'll have to reach for all your tools to get to the bottom of things...

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Specializes in CCU/CVU/ICU.
I also want to know more about st segment elevation. because there is any defined level is given in books for positive or negative in relation to troponin level.

There is no relationship between the amount of st-elevation/depression and how high a troponin will or will not rise.

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hey, we should let the physician worry about the diagnosis. to often us nurses try to diagnose, we arent trained 4 that.

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Specializes in Telemetry.
hey, we should let the physician worry about the diagnosis. to often us nurses try to diagnose, we arent trained 4 that.

You are kidding, right?

I don't know of any doctors who routinely sit at the bedside waiting to enterpret cardiac enzymes and EKGs. And those types of situations where there are elevations and changes are best not left til the doctor's next rounds.

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Specializes in ER, Critical Care, Paramedicine.

Hey, with such a low MB, the troponins are probably trending down. I agree with getting an older ECG to check if the changes are new. I also think you need to explore their recent history to see if there is any reason to suspect ischemia, cardiac strain in the last week or two. Dig deeper then let us know. Remember ST changes need to be in two or more contigious leads and more than 1mm to be significant in most places.

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