1. Among the choices below, there is one incorrect answer. Identify which answer is incorrect.
An acute myocardial infarction is diagnosed when there is a rise or fall of a cardiac biomarker, preferably cardiac troponin, with at least one value above the 99th percentile upper reference limit and at least one of the following:
A. Symptoms of cardiac ischemia
B. Evidence of pulmonary embolism
C. Development of pathological Q waves in the electrocardiogram
D. Imaging evidence of new loss of viable myocardium
The correct answer is B. The presence or absence of a pulmonary embolism is unrelated to establishing a diagnosis of myocardial infarction.
2. Which of the following biomarkers for myocardial infarction is preferred to establish the diagnosis?
A. Creatine kinase-MB fraction (CK-MB)
B. Lactate dehydrogenase (LDH)
C. Cardiac troponin I or cardiac troponin T
D. Aspartate aminotransferase (AST)
The correct answer is C. All of the other choices have been used as markers of myocardial infarction, but troponin T and troponin I are diagnostically superior to all of them.
3. Which of the following biomarkers is most useful to identify congestive heart failure among other causes for shortness of breath?
A. B-type natriuretic peptide (BNP)
The correct answer is A. BNP monitoring has greatly improved the frequency of correct diagnosis of congestive heart failure over the use of clinical judgment and other diagnostic methods. It is the primary biomarker used for identification of congestive heart failure. It is elevated not only in congestive heart failure, but also increases can occur in inflammatory cardiac conditions, arterial and pulmonary hypertension, chronic renal failure, and liver cirrhosis. Troponin elevations may accompany BNP elevations in congestive heart failure.