A case of significantly increased mitral regurgitation early after atrial septal defect closure.

We report a rare case in which mitral regurgitation (MR) was exacerbated to a severe level early after atrial septal defect (ASD) closure, even though the female patient had preoperatively mild MR and mild changes in mitral valve (MV) and sinus rhythm. The mechanism of increased MR was considered as poor coaptation and tethering of the MV due to the restricted motion of the posterior leaflet in addition to geometric changes of the left ventricle (LV) after ASD closure.