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  #1  
Old 12-23-2012
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Heart Question on MI: next best step?

interesting question:

a 63 y/o Female comes with substernal chest pain of 1 hour duration.
She is a K/C/O Afib and is currently on aspirin Prophylaxis for the same. Her EKG shows suspicious T wave inversions in leads II III AvF. She is started on Heparin, Beta Blockers, Aspirin, Clopidogrel. The patient stabilizes. Later her BP falls to 100/60 and her HR to 55/min her Beta Blockers are discontinued.
Currently her EKG shows pauses between beats from 1.2sec to 2 sec. The cardiologist is consulted and is unsure of the suspicious T waves.
What is the next best step to diagnose cardiac ischemia.

A- LDH levels
B- Myoglobin levels
C- Stress Echo
D- Stress EKG
E- Dipyradamole thalium
F- Stress thalium
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  #2  
Old 12-23-2012
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I will go with B(Myoglobin). Stress tests are not done in ongoing chest pain. Myoglobin though not too specific, but rises in 1 hour and seems to be the best choice.
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  #3  
Old 12-23-2012
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Quote:
Originally Posted by doc.mav View Post
I will go with B(Myoglobin).Stress tests are not done in ongoing chest pain.Myoglobin though not too specific,but rises in 1 hour and seems to be the best choice.
myoglobin n LDH are never the right answers for MI. they are too non specific.

a raised myoglobin like u said is very non specific for myocardial ischemia.




(will post the answer in a little bit... let the others preparing take a go at it)
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  #4  
Old 12-24-2012
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Quote:
Originally Posted by mbbs2010 View Post
myoglobin n LDH are never the right answers for MI. they are too non specific.
thats what i was thinking, but the rest of the options are all too similar. stress ekg is the test to do for intermediate suspicion of ischemia, but pt has been on a beta blocker, so pretty much all the physical stress tests are out.
i think dipyridamole thalium will be the best test to confirm or rule out ischemia
E- Dipyradamole thalium
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  #5  
Old 12-24-2012
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Quote:
Originally Posted by theundead View Post
thats what i was thinking, but the rest of the options are all too similar. stress ekg is the test to do for intermediate suspicion of ischemia, but pt has been on a beta blocker, so pretty much all the physical stress tests are out.
i think dipyridamole thalium will be the best test to confirm or rule out ischemia
E- Dipyradamole thalium
The HR is 55, giving dipyradamole is going to cause the HR to further reduce, something we dont want. I think stress Thallium is the answer. It shows the ischemic part without further stress on an already stressed heart.
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Old 12-24-2012
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A & B are ALWAYS WRONG for diagnosis in patients with MI

(except for when the question is which one rises first -- then myoglobin)

Since the patient is bradycardic any kind of stress will be unable to raise the heart rate high enough to interpret any kind of stress test.

Dipyradamole thallium is the test of choice in patients with bradycardia.

hence the answer is E - Dipyradamole Thallium
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  #7  
Old 12-24-2012
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Quote:
Originally Posted by mbbs2010 View Post
A & B are ALWAYS WRONG for diagnosis in patients with MI

(except for when the question is which one rises first -- then myoglobin)

Since the patient is bradycardic any kind of stress will be unable to raise the heart rate high enough to interpret any kind of stress test.

Dipyradamole thallium is the test of choice in patients with bradycardia.

hence the answer is E - Dipyradamole Thallium
I think in acute chest pain any kind of stress test including Dipyradamole thallium are not done....please correct me if I am wrong.
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  #8  
Old 12-24-2012
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Quote:
Originally Posted by doc.mav View Post
I think in acute chest pain any kind of stress test including Dipyradamole thallium are not done....please correct me if I am wrong.
what u are saying is true.
however the question says that she has stabilized and now has bradycardia
(which cud be due to the right sided heart lesion or the beta blockers)

in either case.. to diagnose the ischemia with bradycardia - one would do the above test
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  #9  
Old 12-25-2012
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Quote:
Originally Posted by mbbs2010 View Post
what u are saying is true.
however the question says that she has stabilized and now has bradycardia
(which cud be due to the right sided heart lesion or the beta blockers)

in either case.. to diagnose the ischemia with bradycardia - one would do the above test
Got it.had missed that part in going through the question quickly.Thats how we sometime do the question wrong even if we know the concepts.Good on you.
Good luck for your Step3
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  #10  
Old 12-28-2012
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Quote:
Originally Posted by doc.mav View Post
Got it.had missed that part in going through the question quickly.Thats how we sometime do the question wrong even if we know the concepts.Good on you.
Good luck for your Step3
still feel the question is wrongly framed.Quest says 1 hour ago,ususally stress tests are not done before 48 hours of acute chest pain.
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  #11  
Old 12-28-2012
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Quote:
Originally Posted by Wisconsin View Post
still feel the question is wrongly framed.Quest says 1 hour ago,ususally stress tests are not done before 48 hours of acute chest pain.
maybe.
i just picked it out of a qbank that i was doing.

anyway.. it was the concept behind it that i was unaware of.. so thought of sharing it
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  #12  
Old 12-29-2012
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Quote:
Originally Posted by mbbs2010 View Post
maybe.
i just picked it out of a qbank that i was doing.

anyway.. it was the concept behind it that i was unaware of.. so thought of sharing it
I agree with mbbs 2010 that we should gain from what this question is trying to convey.
Though I am sure in real exam such a quest will be appropriately framed,because any wrongly framed quest can astray you to different answer as it did here.
Wisconsin has rightly mentioned that usually(though not always) cardiologist wait at least 48 hours after acute chest pain before doing stress tests.
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Old 01-04-2013
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thanks buddy i like it .
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