USMLE Step 3 - Question 36

A 27 year old female with no significant past medical history is 40 weeks pregnant and labor has just begun. She begins to complain of shortness of breath which worsens throughout delivery to the point of requiring intubation. She had never previously complained of any dyspnea or chest pains. Her temperature is 37.0, blood pressure 90/50, heart rate 130, respirations 26, and oxygen saturation 100% on 60% FiO2 on the ventilator. Physical examination reveals diffuse pulmonary rales, a II/IV early diastolic murmur, and no lower extremity edema. Laboratory studies are normal. ECG shows sinus tachycardia and left atrial enlargement. Her chest x-ray has significant pulmonary edema. Which of the following is the most likely diagnosis?

A. Aortic dissection

B. Coronary artery dissection

C. Aortic valve stenosis

D. Mitral valve stenosis