Anomalies of the left atrium and mitral valve. Cords, flaps, and duplication of valve

We studied seven hearts with abnormalities of the atrial septum or the mitral valve. Three had abnormalities of the atrial septum, characterized by a flap or a diaphragm within the left atrium. Another three cases had abnormal cords extending from the atrial septum to the anterior or the posterior mitral leaflets. A seventh case had a duplicated mitral valve. Grossly, the specific conditions among these seven hearts appeared very different; however, we believe that the origin of each anomaly can be explained by one of three developmental aberrations or a combination hereof. Although only one case was associated with severe cardiac disease, such structures may be seen during cardiac imaging or operation.