A 64-Year-Old Man Comes to the Emergency Department Due to Chest

A 64-year-old man comes to the emergency department due to chest discomfort and shortness of breath.  Medical history includes hypertension, type 2 diabetes mellitus, and severe osteoarthritis of the left knee.  The patient is an active smoker with a 20-pack-year smoking history.  He undergoes dobutamine infusion with simultaneous cardiac imaging.  The following is seen:Before infusion: normal left ventricular contractility, ejection fraction 60%During infusion: decreased apical contractility, ejection fraction 45%Five minutes after infusion: normal left ventricular contractility, ejection fraction 60%Which of the following best explains the observed findings?

A) Coronary artery occlusion due to plaque thrombosis
B) Coronary artery vasospasm
C) Focal myocardial fibrosis
D) Normal myocardial contractile response
E) Supply-demand mismatch due to fixed coronary stenosis

Correct Answer:

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