Question 82

Question:

A 76-year-old obese woman with a history of type II diabetes and heart disease presents complaining of crushing sub-sternal chest pain of 30 minutes duration with pain radiating down her left arm. A blood test within 8 hours would show an increase in which of the following cardiac enzyme levels?

Correct Answer: E.  Troponin I

Of the choices listed, Troponin-I is the best enzyme level to evaluate. Troponin-I is immediately elevated for up to 8 hours post-MI and continues to stay elevated for about 7 days. Creatine phosphokinase (CPK) is also sensitive and can be used instead of Troponin-I, although this was not a choice.
AST is increased after Troponin-I and peaks later.
LDH is increased after AST and peaks later.
It is important to learn to the pathophysiology of myocardial infarctions, as well as the characteristic lab tests used to determine relative damage/timing.