Mild cough · wheezing · loud heart sounds · Dx?

A 25-year-old man, who was an active duty US Navy sailor, went to his ship's medical department complaining of a mild cough that he'd had for 2 days. He denied having any fevers, chills, night sweats, angina, or dyspnea. He said he hadn't experienced any exertional fatigue or difficulty completing the rigorous physical tasks of his occupation as an engineman on the ship. The patient had no medical or surgical history of significance, and he wasn't taking any medications or supplements. On exam, he was not in acute distress and his vital signs were within normal limits. Auscultation revealed mild wheezing throughout the upper lung fields and loud heart sounds throughout his chest that were audible even with gentle contact of the stethoscope diaphragm. He had no discernible murmurs, rubs, or gallops. In light of the unusually loud heart sounds heard on exam, we performed an electrocardiogram. The EKG revealed a normal sinus rhythm, slight right axis deviation indicated by tall R-waves in V1 (also suggestive of right ventricular hypertrophy), an incomplete right bundle branch block, and a crochetage sign (a notch in the R-waves of the inferior leads). A chest x-ray revealed a normal-sized heart and dilated pulmonary vasculature suggestive of pulmonary hypertension.