Review Question - QID 212665

A 55-year-old woman presents to the emergency department with retrosternal pain that started this evening. The patient states that her symptoms started as she was going to bed after taking her medications. She describes the pain as sudden in onset, worse with swallowing, and not associated with exertion. The patient has a past medical history of diabetes, anemia, and congestive heart failure and is currently taking metoprolol, insulin, metformin, iron, and lisinopril. Her temperature is 99.2°F (37.3°C), blood pressure is 125/63 mmHg, pulse is 90/min, respirations are 14/min, and oxygen saturation is 100% on room air. Physical exam is notable for an obese woman who appears uncomfortable. An initial electrocardiogram (ECG) demonstrates sinus rhythm, and a set of troponins are pending. Which of the following is the most likely diagnosis?