A 37-year-old, physically active man presented for evaluation of nonexertional chest pain. He described it as sharp, left-sided, and nonradiating. The review of systems was unremarkable. He had had no previous thoracic surgery. Physical examination revealed a nonpalpable apical impulse, with no other abnormal findings. A chest radiograph (Figure 1) demonstrated a prominent pulmonary artery shadow, with leftward and posterior rotation of the cardiac …