Mitral insufficiency ring is typically secured to the annulus, or opening of the mitral valve, to provide additional structural support. In some cases, the "double orifice" (or 'Alfieri') technique for mitral valve repair, the opening of the mitral valve is sewn closed in the middle, leaving the two ends still able to open. This ensures that the mitral valve closes when the left ventricle pumps blood, yet allows the mitral valve to open at the two ends to fill the left ventricle with blood before it pumps. In general, mitral valve surgery requires "open-heart" surgery in which the heart is arrested and
Mitral valve away from the free margin. This disposition has important effects on systolic stress distribution physiology The mitral annulus is a fibrous ring that is attached to the mitral valve leaflets. Unlike prosthetic valves, it is not continuous. The mitral annulus is saddle shaped and changes in shape throughout the cardiac cycle. The annulus contracts and reduces its surface area during systole to help provide complete closure of the leaflets. Expansion of the annulus can result in leaftlets that do not join soundly together, leading to functional mitral regurgitation. The normal diameter of the mitral annulus is , and the circumference