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Internal Med Case Questions

Terms in this set (42)

D. Electrocardiogram (ECG)

The first step in evaluating this patient with severe chest pain is an ECG. An ECG can differentiate an ST-segment elevation myocardial infarction from the other acute coronary syndromes. It can also provide other evidence of coronary ischemia, including T-wave inversion and ST-segment depression. Since the outcome of a myocardial infarction depends on timely intervention, rapid identification is essential and an ECG is the most efficient diagnostic test.
A chest X-ray may be reasonable for evaluating the source of the chest pain, but with normal vital signs and lung exam, and a primary complaint of anginal chest pain, an ECG should be performed first.
A complete blood count would be helpful in evaluating for infection or an acute anemia which could be contributing to the patient's presenting symptoms, but it is a nonspecific test that would not be useful in the timely evaluation for acute coronary syndrome.
A CT angiogram of the chest would be obtained to evaluate for pulmonary embolism. This may be appropriate if acute coronary syndrome is ruled out, and suspicion for pulmonary embolism increases. However, the lack of pleuritic chest pain, tachycardia, and hypoxia makes this diagnosis less likely.
A troponin test may also be helpful in identifying an acute coronary syndrome in this patient, but the process of drawing blood and lab analysis will take time, during which she could already be receiving appropriate treatment. Additionally, since her pain began only two hours earlier, it is possible that the troponin measurement may be negative. In some instances, depending on the troponin assay used, serum troponin elevations may not be detectable for four to eight hours after onset of anginal symptoms.