Question: A 74-year-old man presents to the clinic for heartburn. He states that the heartburn occurs most often when he goes on his morning walks and while working in his yard, and it improves within a couple minutes when he sits down and rests. He states that he has taken over-the-counter antacids without improvement. Which of the following diagnoses is most likely? Acute myocardial infarction Microvascular angina Stable angina pectoris Variant angina