<prompt> A 34-year-old man presents with dyspnea and increasing peripheral edema. He recently had a flu-like illness with intermittent sharp left-sided chest pain. On examination, his jugular venous pressure JVP is elevated at 8 cm, heart sounds are soft, and the blood pressure BP is 10476 mm Hg with a 20 mm Hg decrease in systolic arterial pressure during slow inspiration. Which of the following is the most likely diagnosis?cardiac tamponadepulmonary hypertensionventricular septal defectcoarctation of the aorta  <response>: The drop in systolic pressure with inspiration is an important clue to cardiac tamponade, called pulsus paradoxus. When severe, the arterial pulse may weaken on palpation during inspiration. Pulsus paradoxus is uncommon in constrictive pericarditis and rare in restrictive cardiomyopathy. It is commonly found in severe asthma as well. 