A 35-year-old man presented with intermittent shortness of breath and paroxysmal cough that had been present for two weeks. His symptoms were managed conservatively, and he was discharged. Two weeks later, the patient described a burning sensation in his chest that accompanied his coughing episodes. Additionally, his shortness of breath had become persistent, and he reported general deconditioning, such as difficulty in performing his daily aerobic exercise. The patient had borderline hypertension controlled with lifestyle measures, but no other significant medical history. He had never smoked and did not regularly use any medications. The patient did not have a significant family medical history.

The patient used a clenched fist at the chest (Levine sign)¹ to describe his discomfort, but physical examination findings and measurement of vital signs were unremarkable. Due to the patient's use of Levine sign and his history of borderline hypertension, electrocardiography was performed (Figure 1).

Question

Based on the patient's history and physical examination findings, which one of the following is the most likely diagnosis?