USMLE Step 2 - Question 49

A 68 year old female with a history of hypertension and diabetes presents with chest pains intermittently for 4 days and now significantly worse acute onset shortness of breath. Her temperature is 37.1, blood pressure 85/65, heart rate 110, respirations 24, and oxygen saturation 79% on room air. Physical examination reveals diffuse pulmonary rales, a II/VI holosystolic murmur at the cardiac apex radiating to the axilla, and elevated jugular venous pressure. A Swan-Ganz catheter is inserted and the pulmonary capillary wedge pressure tracing shows large V waves. Her ECG shows significant ST segment elevation. Which of the following coronary arteries is the most likely culprit?

A. Left main coronary artery

B. Left anterior descending coronary artery

C. Left circumflex coronary artery

D. Right coronary artery