Mitral valve prolapse with left atrial enlargement out of proportion to mitral regurgitation.

Chronic severe mitral regurgitation (MR) is associated with compensatory dilation of the left atrium (LA) and left ventricle (LV). However, LA enlargement is not unique to patients with MR. Herein are reported the details of nine patients with mitral valve prolapse (MVP) and no more than mild MR, but in whom the LA enlargement is out of proportion to the MR severity. Because of the potential to overestimate MR severity using an integrative echocardiography/Doppler approach that includes evidence of chamber dilation in the diagnosis of severe MR, there may be significant clinical implications if the connective tissue abnormality underlying MVP or other factors results in an independent enlargement of the left atrium.