Q13
Single choice
A 65-year-old man presents to the emergency department with an abrupt onset of excruciating chest pain 1 hour ago. The pain is localized to the anterior chest, but radiates to the back and neck. On examination, the patient is afebrile, with a BP of 210/110 mmHg, pulse rate of 95/min, and a respiratory rate of 12/min. He appears pale and sweaty. Unequal carotid, radial, and femoral pulses are noted. An electrocardiogram (ECG) shows nonspecific ST-T segment changes. Chest x-ray shows a slightly widened mediastinum and normal lung fields.
Which of the following is the preferred modality in establishing the diagnosis?