• Images in cardiology

A 46 year old man presented with a short history of flu like symptoms and the clinical finding of atrial fibrillation. Transthoracic echocardiography raised the suspicion of a poorly defined membrane within the left atrium. Transoesophageal echocardiography demonstrated a thick membrane dividing the left atrium into a common pulmonary venous chamber, receiving the pulmonary veins, and the true left atrium (panels A and B). This was attached medially to the margin of the fossa ovalis and laterally to the junction of the left superior pulmonary vein and the left atrial appendage. Doppler studies estimated the mean trans membrane pressure gradient at 2 mm Hg. The images were consistent with the diagnosis of cor triatriatum sinister.

Surgical excision of the left atrial membrane was performed and the patient made a full recovery.

Transoesophageal echocardiography in systole (A) and diastole (B) demonstrating the left atrial membrane (white arrows). CPVC, common pulmonary venous chamber; LA, true left atrium; LV, left ventricle; RV, right ventricle; RA, right atrium.