Incidental Finding of a Rare Left Atrial Appendage Anomaly: A Case Report

Introduction. Congenital hypoplasia of the left atrial appendage (LAA) with stenotic ostium in an abnormal position is an extremely rare entity. We report an exceptional case of hypoplastic LAA with ostial stenosis in an abnormal location in the patient with mitral valve stenosis that was mistaken in the transesophageal echocardiography (TEE) for an intraluminal thrombus. Case report. A 43-year-old woman was admitted to our center with dyspnea on exertion. TEE revealed the presence of severe mitral stenosis and clot in the LAA. The patient underwent open cardiac surgery by cardiopulmonary bypass. Intraoperative inspection of the left atrium revealed hypoplasia of the LAA with stenotic and slit-like ostium. There was also a malposition of the LAA that was placed in a paravalvular location. The ostium of the LAA was not round and wide but narrowed and slit-like. Conclusion. The authors believe that this anomaly may have some physiologic consequences in patients with mild structural failure. Indeed, this anomaly may aggravate the severity of structural failure by pressure burden on the atrial wall and valve.