A 50-year-old man, who is an active smoker without a previous medical history, was admitted for recent dyspnea (New York Heart Association functional class III) and an episode of exertional syncope. His familial history included the sudden death of his mother at the age of 50. His blood pressure was 123/90 mm Hg; heart rate, 80 beats/min; peripheral oxygen saturation, 95%; and clinical examination found a prominent pulmonary component of S2, jugular vein distension, and normal lung sounds. His ECG showed complete right bundle-branch block. Chest radiography showed central pulmonary artery, right atrium, and ventricle enlargements without major abnormalities of pulmonary parenchyma (Figure 1). Brain natriuretic peptide was 758 pg/mL (normal, <100 pg/mL) and troponin T was raised to 0.22 ng/mL (normal, ≤0.14 ng/mL). Figure 1. Chest radiograph shows bilateral hilar, right atrium, and ventricle enlargements resulting from pulmonary hypertension. Pulmonary parenchyma was normal. Transthoracic echocardiography showed severe dilatation of the right chambers, paradoxical wall motion septum, and pulmonary hypertension with a tricuspid regurgitant jet velocity of 4.5 m/s and an estimated systolic pulmonary arterial pressure of 96 mm Hg (Figure 2). Left ventricle, aortic and mitral valves, and left …