Review Question - QID 212357

A 55-year-old man is seen in the hospital for new onset shortness of breath. The patient was hospitalized 5 days ago after initially presenting with chest pain. He was found to have an ST-elevation myocardial infarction. He underwent percutaneous coronary intervention with stent placement to resolve his chest pain. He states that he was doing well until yesterday when he developed dyspnea while walking around the hall and occasionally when getting out of bed to use the bathroom. His shortness of breath has since progressed, and he is now having trouble breathing even at rest. His medical history is also significant for type 2 diabetes mellitus and hypercholesterolemia. He takes aspirin, clopidogrel, metformin, and atorvastatin. His temperature is 97°F (36.1°C), blood pressure is 133/62, pulse is 90/min, respirations are 20/min, and oxygen saturation is 88% on room air. On physical examination, there is a holosystolic murmur that radiates to the axilla and an S3 heart sound. Coarse crackles are heard bilaterally. An electrocardiogram, a chest radiograph, and cardiac enzyme levels are pending. Which of the following is the most likely diagnosis?