Systolic anterior motion occurs after mitral valve repair due to an excess of leaflet tissue versus the anterior lateral height of the orifice of the mitral valve. The posterior leaflet pushes the anterior leaflet into the outflow tract. There are two principal causes for this. One is excess height of the posterior leaflet after reconstruction. The second one is a ring size that is too small for the available leaflet tissue. In either circumstance, the posterior leaflet will coapt at the midpoint of the anterior leaflet, and the tip of the anterior leaflet is pushed into the outflow tract.