We describe two cases of an isolated cleft of the mitral valve in transposition with intact ventricular septum. The cleft is positioned leftward in the pulmonary leaflet, at about 2 o’clock, when viewed from below looking at the cardiac short axis with the right ventricle to one’s left hand. Such clefts, when seen in the Taussig-Bing malformation are also positioned leftward.
In keeping with our current knowledge of cardiac development, our cases provide further evidence that transposition with an intact ventricular septum is the end-point of the Taussig-Bing spectrum.
