Mechanism of mitral regurgitation in hypertrophic cardiomyopathy

Differences in leaflet length and mobility influence the extent of mitral regurgitation.
Panel A: The anterior and posterior mitral valve leaflets visibly coapt over a longer distance (contact length, C), resulting in a small amount of mitral regurgitation.
Panel B: The posterior leaflet is limited in its ability to move anteriorly, and the mitral leaftlets fail to coapt, resulting in a visible gap (G) and a greater degree of mitral regurgitation. The ability to coapt is determined both by the length of the posterior leaflet and by the range of motion permitted by its chordal and papillary muscle connections.