To view this video please enable JavaScript, and consider upgrading to a web browser that supports HTML5 video Video 1 Cleft in the posterior leaflet of the mitral valve viewed from the left atrium by 3D transoesphageal echocardiography. View Video 1 at http://movie-usa.glencoesoftware.com/video/10.1530/ERP-18-0074/video-1. Three-dimensional echocardiography in congenital heart disease John M Simpson, and Annemien van den Bosch 2019. 6:R75-R86 DOI: 10.1530/ERP-18-0074 Download Original Video