Is there another type of biventricular atrioventricular connection?

In evaluating a 9-year-old girl, we encountered the following cardiac anomalies: a left atrioventricular valve (the morphologic left atrium on the left side, connected with the morphologic left ventricle); concordant atrioventricular connections; a right atrioventricular valve (a morphologic right atrium on the right side, connected with the morphologic right ventricle); concordant atrioventricular connection; a "central" atrioventricular valve (separating the morphologic right atrium from the morphologic left ventricle); and discordant atrioventricular connection with intact interatrial and interventricular septa. A right-to-left shunt passed through the central valvular structure, which was situated at the atrioventricular septum. This was the only means of mixing pulmonary and systemic blood. We suggest that this case presents a newly recognized cardiac anomaly.