A 47-year-old man presented to his general practitioner complaining of a persistent cough associated with wheezing. It was felt that he may have had asthma and was treated with a salbutamol inhaler. However, returned to his G.P. 1 month later with the same symptoms. Oral theophylline was commenced. Due to the persisting symptoms he was referred to our chest clinic. In the clinic, he reported his history of a cough with wheeze and also that he had had bouts of dyspnoea and episodes of pain in his left shoulder, but these had largely resolved. He was a life long non-smoker, who had worked as a reception engineer in a garage. He had no past history of any illnesses. On examination he was a little overweight and mildly hypertensive. His peak flow was 560 1 mint and his chest X-ray showed his heart to be slightly enlarged. His ECG was normal. At the time, it was felt that the symptoms may have been due to bronchial hyper-reactivity, possibly related to a resolved chest infection. Eight months later he was admitted to hospital acutely dyspnoeic, following a 3-week history of progressive exertional dyspnoea, only being able to walk about 20 m on the flat. He had also had exertional nearsyncope, intermittent left-sided chest pains and a cough productive of yellow sputum. On examination he was mildly centrally cyanosed but not distressed, nor clubbed. He had a resting tachycardia at 120 beats per rain and a blood pressure of 130]70. His JVP was raised 4 cm. On auscultation of his heart, he had a loud P2 component of the second heart sound and a pansystolic murmur at the left sternal edge, and a third sound over the right ventricle. A systolic bruit could be heart over his right hemithorax. His breath sounds were vesicular with no extra sounds. The chest X-ray revealed a large heart with an oligaemic left lung and a left hemithorax slightly