Cor triatriatum sinistrum is rare congenital cardiac malformation. It accounts for approximately 0.1-0.4% of all patients with congenital heart disease. Most cases are diagnosed in childhood, while adult cases are very rare. The condition is characterized by the presence of a fibromuscular membrane dividing the left atrium into two chambers a superior posterior chamber and an inferior anterior chamber. A 30-year-old male presenting with progressive exertional dyspnea for the past two years was admitted to our clinic. Color Doppler ultrasonography revealed an eccentric, mosaic pattern of continuous turbulent flow near the interatrial septum across the membrane. The peak velocity of the flow across the membrane was 2.70 m/s, indicating that the pressure gradient between two chamber was 11.5 mmHg. Surgical correction of the membrane was recommended. The membrane was excised and all symptoms resolved in the scheduled visit at one month following surgery. In this article, we report an adult case of incomplete cor triatriatum sinister with a significant pressure drop.

Keywords : Cor triatriatum sinister; surgical correction; transesophageal echocardiography