A 64 year old woman presented with a six month history of progressive exertional dyspnoea and paroxysmal nocturnal dyspnoea. Echocardiography showed severe pulmonary hypertension, concentric left ventricular hypertrophy, normal systolic function, and no evidence of shunting by saline contrast. The 12 lead ECG exhibited atrial fibrillation. Chest radiography and computed tomography …