Q. A 70-year-old woman presents to the emergency department with crushing substernal chest pain radiating to her neck and jaw. Her hospital records show an MI 10 years ago along with a history of DM2, and a BMI of 30. Emergency cardiac catheterization with percutaneous coronary intervention (PCI) shows a 99% occlusion of her left anterior descending artery, and an EKG reveals an anterior wall ST segment elevation MI. The patient remains stable after PCI, and a cardiac echo shows an ejection fraction (EF) of 45%. Three days later, the patient becomes acutely hypotensive and dyspneic. A physical examination reveals a new-onset high-pitched holosystolic murmur, loudest at the apex and radiating to the axilla. An echocardiogram shows an EF of 25%. This patient has developed which of the following?