A 14-year-old boy was admitted with a 2-week history of increasing breathlessness and fatigue. He had a pulse rate of 130 beats/min and blood pressure of 100/66 mmHg with 16 mm paradox. Jugular venous pressure was raised 10 cm above the sternal angle, and heart sounds were faint. He had been diagnosed with refractory iron-deficiency anaemia in early childhood, for which he had been receiving blood transfusions. He denied any history of epistaxis, haemoptysis, malaena, haematuria or overt bleeding from any other site.