<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 36-year-old man presents to his physician with an acute burning retrosternal sensation with radiation to his jaw. This sensation began 20 minutes ago when the patient was exercising at the gym. It does not change with position or with a cough. The patients vital signs include: blood pressure is 14090 mm Hg, heart rate is 84min, respiratory rate is 14min, and temperature is 36.6C 97.9F. Physical examination is only remarkable for paleness and perspiration. The patient is given sublingual nitroglycerin, the blood is drawn for an express troponin test, and an ECG is going to be performed. At the moment of performing ECG, the patients symptoms are gone. ECG shows increased R amplitude in I, II V3-V6, and ST depression measuring for 0.5 mm in the same leads. The express test for troponin is negative. Which of the following tests would be reasonable to perform next to confirm a diagnosis in this patient?? A: Blood test for CPK-MB, B: Echocardiography, C: Chest radiography, D: CT angiography, E: Exercise stress testing,  <response>: This is a clinical case scenario describing a patient with acute chest pain suggestive of angina. The key findings are retrosternal chest pain brought on by exertion, relieved by rest, associated with diaphoresis and pallor. The ECG shows ST depression consistent with ischemia. The troponin is negative, ruling out myocardial infarction. The question asks about the next reasonable test to confirm the diagnosis. Choice A tests CPK-MB which is an enzyme elevated in myocardial infarction - this has already been ruled out by the negative troponin. Choice B, echocardiography, may show wall motion abnormalities if there was myocardial infarction or ischemia, but is not the next best step. Choice C, chest x-ray, is not useful to evaluate angina. Choice D, CT angiography, is an anatomical test that shows coronary artery stenosis but is not the next logical step. Choice E, exercise stress testing, is the best answer. This is a functional test that would confirm exertional angina in the setting of a normal resting ECG. Exercise stress testing provokes the symptoms and ECG changes of ischemia to confirm the diagnosis.E: Exercise stress testing 