A 63 year old woman presented to her local hospital with a painful anterior chest wall swelling. Two years previously she had undergone uncomplicated aortic valve replacement (mechanical prosthesis) and coronary artery bypass grafting. She had remained well following her surgery until three months before presentation when she had first noticed chest wall discomfort. The swelling had progressively enlarged until the time of presentation.

Examination revealed a 12 × 8 cm pulsatile swelling over the left parasternal region with a palpable thrill. She was otherwise well with normal prosthetic valve sounds. Subsequent transthoracic and transoesophageal echocardiography, computed tomography, magnetic resonance imaging, and aortography demonstrated a large fluid filled cavity anterior to the right ventricle, compressing the right ventricle and outflow tract, and containing an epicardial pacing lead. No communication with the aorta or cardiac chambers could be identified.

After preparation for femoral bypass the median sternotomy was reopened and a large presternal haematoma was identified in association with necrotic costal cartilage. The haematoma was evacuated but again no communication could be identified; following evacuation of the haematoma there appeared to be good haemostasis. It was hypothesised that the palpable pulsation had been transmitted from the pulmonary artery

Initial progress was satisfactory, but the patient’s subsequent clinical course was complicated by recurrence of the swelling and several episodes of recurrent bloody discharge from a sinus on the chest wall requiring further hospital admission, culminating in a profuse, self limiting haemorrhage causing haemodynamic collapse. At this time coronary angiography demonstrated a false aneurysm of the body of the left anterior descending (LAD) vein graft (fig 1), but no track to …