FOAMed

An 83-year-old female presents to the ED with dyspnea at rest following a syncopal episode. Patient reports she was out for a walk with her husband when she began to feel lightheaded, short of breath, and then fainted. Triage vitals include BP 88/50, HR 115, RR 24, O2 98%. ECG is without signs of acute ischemia. On exam, the patient appears slightly tachypneic, with rales noted at bilateral lungs. There is a systolic murmur along with 2+ pitting edema at the lower extremities. Cardiac POCUS shows grossly decreased left ventricular EF with a hyperechoic structure at the aortic valve. What is the most likely diagnosis?