What are five echocardiographic criteria for diagnosing mitral valve prolapse?

1. Thickened mitral leaflets (>0.5 cm) with myxomatous degeneration.
2. Redundancy of the leaflets.
3. Posterior displacement of any leaflet more than 3 mm beyond the mitral annular plane in the parasternal long axis. (The apical window is far less sensitive for this finding owing to the saddle shape of the mitral annulus.)
4. Posterior displacement of the posterior leaflet on M-mode echocardiography.
5. Late systolic regurgitation.