Left atrial septal pouch causing an ischaemic stroke in association with aortic coarctation

A 61-year-old lady presented with recurrent right middle cerebral artery (MCA) territory stroke. She had a previous stroke 3 years earlier which was investigated with transthoracic echocardiogram, Holter monitor, and carotid Doppler, but no thrombo-embolic source was identified. She has been on Asasantin® SR 200/25 for secondary stroke prevention since then. She also had a history of hypertension secondary to coarctation of the descending thoracic aorta which was successfully treated with endoluminal stenting when she was 59 years old. During this presentation, brain magnetic resonance imaging scan confirmed acute right MCA territory cerebral infarction. Carotid Doppler, transthoracic echocardiography, and Holter monitoring were repeated without showing a thrombo-embolic source. She was then referred for a transoesophageal echocardiogram (TOE) which showed a large left atrial septal pouch with heavy spontaneous echo contrast and possibly a small thrombus (Panel A); the pouch measured 12 × 17 mm and was communicating with the left atrial cavity (Panel B). No inter-atrial communication was detected by agitated saline injection and stagnant flow in the pouch was demonstrated by colour Doppler (Panel C).