Abstract
Inverted left atrial tissue is mostly identified when the heart is empty while coming off bypass. During echocardiography a new, echodense mobile mass in the left atrium without attachment is visualized. Such a picture can easily produce not only confusion in the diagnosis but also mitral valve obstruction, hemodynamic instability, and a possibility of appendage necrosis. Inability to identify such inverted tissue can lead to unwanted interventions with additional cardiopulmonary bypass time.