Congenital mitral valve disease in transposition of the great arteries.

A spectrum of mitral valve disease was noted in 71 per cent of 163 specimens with transposition of the great arteries. At one end of the spectrum were hearts with normal mitral valve, except that the free margin of the anterior leaflet was shortened; at the other end were specimens with underdevelopment of the space between or behind the papillary muscles of the left ventricle. In additional specimens the anterior leaflet was indented and attached by chordae tendineae to the ventricular septum.