A 47-year-old female presented with worsening insidious symptoms of breathlessness and leg swelling over the last 12 months. Whilst her ECG and chest X-ray were relatively unremarkable on admission, an echocardiogram demonstrated a large-sized left atrial myxoma. This tumour was resected by the cardiac surgeons the next day, with very good postoperative results. The ensuing discussion details the anatomy and physiology of myxomas, their epidemiology, clinical features, diagnostic investigations and management.