Large Left Atrial Myxoma Presenting as Functional Mitral Stenosis: A Multimodal Imaging Case Report.

A 71-year-old woman with no prior cardiac history presented to the cardiology clinic following referral from her primary care physician for evaluation of progressive dyspnea, fatigue, and palpitations over a six-month period. Transthoracic echocardiography revealed a large, mobile mass attached to the interatrial septum measuring 6.4×3.9 cm, consistent with a left atrial myxoma. There was evidence of left ventricular inflow obstruction, with a mean mitral valve gradient of 15 mmHg. Further assessment determined that the mass was causing functional severe mitral stenosis, resulting in impaired left ventricular filling. A transesophageal echocardiogram confirmed the presence of the mass. The patient subsequently underwent surgical resection of the tumor via cardiopulmonary bypass. Intraoperative findings confirmed a left atrial myxoma measuring 7.1×7×4 cm. This case highlights a rare presentation of a rapidly enlarging atrial myxoma leading to functional mitral stenosis.