Mitral hemi-arcade: an unusual modification of a rare anomaly.

Congenital anomalies of the mitral valve are rare. A mitral arcade is defined as a fibrous continuity between the papillary muscles and the anterior mitral leaflet creating a hammock like suspension. We present images of a mitral anomaly that consists of a direct attachment of the anterolateral papillary muscle to the anterior mitral leaflet, which we have labeled as a "hemi-arcade." We discuss the surgical findings and review the available literature regarding a mitral "arcade".