As a consequence of advances in cardiac imaging, mitral valve prolapse (MVP) has become a commonly recognized finding, occurring in 2.5% to 5% of the general population. Original concepts of MVP were based on limited experience with highly select groups of subjects with nonejection clicks and mid to late systolic murmurs. Such subjects were typically found to have systolic billowing of the mitral valve leaflets into the left atrium on angiographic evaluation. lv2 Pathologic examination of affected valves often demonstrated myxomatous changes with disruption of collagen. 3 Furthermore, follow-up of highly selected patients with MVP4s5 suggested increased risk for infective endocarditis, progressive mitral regurgitation, ruptured chordas, and sudden cardiac death.

The advent of M-mode echocardiography permitted noninvasive detection of mitral leaflet displacement (prolapse) into the left atrium. This finding has been found to be associated with angiographic evidence of billowing mitral leaflets in subjects with the click-murmur syndrome. 6s7 Two-dimensional echocardiography has been proposed, in advance of adequate validation studies, as the best available standard for the diagnosis of MVP. 8 The ease with which mitral valve motion is depicted by echocardiography has resulted in widespread use of this tool for the definition of MVP. Owing to ease of detection and expanding interest in MVP, the medical literature swells with case reports of associations between MVP and an evergrowing list of clinical features and sequelae. It is no surprise that MVP was described in the 1970s as the “cardiac disease, of the decade.“g Recent studies, however, have underscored the benign clinical course of MVP, raising questions about the very existence of a “mitral valve prolapse syndrome.”