Massachusetts General Hospital, Boston, MA, USA.
To what extent is prolapse of the mitral valve associated with mitral regurgitation and the risk of infective endocarditis, rupture of the chordae tendineae, and sudden death? Earlier studies used differing definitions and criteria, and reported prevalence of this deformity varied widely, especially between referral and general population studies. Advances in echocardiography have clarified the diagnosis, allowing classification of prolapse into subtypes associated with different degrees of risk and prognoses.