P1335 Cor triatriatum sinister: the importance of multimodality imaging
Authors: Asla Ormaza C , Manzanal Rey A , Garcia Ibarrondo N , Codina Prat M , Ramirez-Escudero Ugalde G , Aurrekoetxea Bajeneta G , Bravo Martinez I , Castellanos Alcalde M , Ugedo Alzaga K , Lambarri Izaguirre A , Candina Urizar R , Ruiz Gomez L 
Published: January 2020

Abstract
A 67-year-old woman who had previous history of hypertension and hyperlipidemia was referred to the cardiologist because of nonspecific electrocardiographic abnormalities. During physical exam a systolic murmur was detected. Transthoracic echocardiography (TTE) showed aortic valve sclerosis with no evidence of valvular stenosis. An unexpected finding was the presence of a membrane at left atrium (LA) and a transesophageal echocardiography (TEE) was recommended with suspicion of cor triatriatum. No signs of obstruction to LA flow were demonstrable with pulsed-wave or colour Doppler analysis. On 3D TEE imaging, a structure compatible with a left atrial tendon was visualized. To complete the study computed tomography (CT) was performed, revealing the presence of a real membrane dividing the LA into two components, separating the pulmonary veins from the true LA chamber with the left atrial appendage (LAA), being the patient diagnosed of cor triatriatum.
Cor triatriatum sinister (CTS) is a rare but well-recognised form of congenital heart disease. It is believed to reflect failure of incorporation of the common pulmonary vein into the LA. Defining the relationship between the CTS membrane and the LAA allows differentiation from a supra­mitral ring. In CTS, the membrane is located superior to the LAA (between the LAA and pulmonary veins), while a supra­mitral ring is located inferior to the LAA and is often adher­ent to, and constitutes part of, the mitral valve leaflets.
The diagnosis of CTS may be made at any age. Most cases involve a nonobstructive membrane, diagnosis of which is facilitated by advances in imaging technology. TTE is adequate to define the clinical relevance of CTS but it may be more precisely tailored with cardiac CT or cardiac magnetic resonance (CMR) imaging. This case emphasizes the importance of a multimodality imaging approach.
CTS can present as an isolated lesion, but it is more commonly seen in association with other congenital cardiac anomalies (patent foramen ovale, atrial septal defect, patent ductus arterio­sus, coarctation of the aorta, persistent left superior vena cava, ventricular septal defect, anomalous pulmonary venous drainage, and a variety of left-sided cardiac abnormalities).
Nonobstructive asymptomatic adults do not require intervention. However, onset of any cardiovascular symptom should prompt detailed evaluation. A turbulent jet arising from the opening in an obstructive CTS membrane may produce jet lesions on the structurally normal mitral valve causing damage and secondary mitral regurgitation. Surgi­cal resection is the first line of management for an obstructive membrane in the LA. The development of atrial fibrillation in an individual with nonobstructive CTS may also constitute an indication for surgi­cal resection as the presence of the membrane may increase the risk of thromboembolic events.
Abstract P1335 Figure. Cor triatriatum sinister (TTE,3D-TEE,CT)