A 64-y/o woman is referred to ED immediately after office echocardiogram. Complains of ~5 weeks occasional shortness of breath, intermittent mild pain radiating from L shoulder to chest. ECG 3 wks ago, normal. HR: 99 bpm, RR: 23, BP: 139/66, SpOâ: 90% RA.
What is the most likely diagnosis?