MSFinals-0197
A 51-year-old woman with a history of hypothyroidism experiences a collapse during her yoga class. She has been reporting occasional chest pains and difficulty breathing during exercise in the past few weeks. During her physical examination, an ejection systolic murmur is detected at the right upper sternal edge, and her second heart sound is faint. Additionally, she has a slow-rising pulse. What is the most probable cause of her symptoms?