A very unusual combination of straddling and overriding of the tricuspid valve associated with clefting of the mitral valve.

We describe a patient in whom we found dual orifices in a straddling and overriding tricuspid valve, with two normally sized ventricles and a cleft in the mitral valve. The patient underwent successful surgical repair. We discuss the concept of "double-orifice right atrium", as well as the need to differentiate the isolated cleft of the morphologically mitral valve from the zone of apposition between the left ventricular components of the bridging leaflets seen in the setting of atrioventricular septal defect with common atrioventricular junction. We emphasise the unusual association of these abnormalities of the right and left atrioventricular valves in patients with separate atrioventricular junctions.