To the Editor: In the review article by Verma and Mesana (Dec. 3 issue),1 mitral-valve prolapse is defined as the displacement of some portion of one or both mitral-valve leaflets into the left atrium during systole. This term was introduced in 1966 by Criley et al.2 and has been frequently used as a synonym for “billowing mitral leaflet,” which was used by Barlow et al.3 to describe the same condition. Unfortunately, imprecise terminology may have important implications for mitral-valve repair. According to Carpentier,4 the term “prolapse” should be reserved to indicate that the free edge of the leaflet protrudes beyond . . .