Because we don't have anything else that is, overall, "better"!
That is the short answer.
A more full answer....
First off, CKMB and Troponin I are primarily markers for infarction, not ischemia. Ischemia indicates inadequate blood flow, and leads to angina (chest pain), but does not release CKMB and Troponin. Infarction indicates cell death...and release of these chemical markers.
These chemicals and others similar are all throughout the body in muscles. The heart is a muscle to, and releases these chemicals. During a myocardial infarction (heart attack; i.e. heart muscle cell death), CKMB and Troponin are released.
These two are MOST specific for the heart (particularly Troponin I) and released in such a way that we can detect in lab work after (or during) a heart attack.
Therefore, we use them.
We don't have anything better in clinical medicine, yet. Or if we do, it is too expensive, still in research phase, takes to long to analzye during an attack to be useful, and/or simply hasn't been adopted in widespread use in hospitals...
They (particularly the Troponin I) do a pretty good job - more specific and sensitive than anything else (that is, pretty accurate overall).
Other chemicals are not as sensitive and/or specific...making them pretty useless (namely, because other muscles release them and confuse the clinical picture).
Well, I am not sure if this was what you were looking for, but I hope it helps...
2006-10-27 15:44:10
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answer #1
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answered by yachadhoo 6
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