A criss-cross heart. Detailed anatomic description and discussion of morphogenesis.

Hearts with criss-cross atrioventricular connections are rare. Reports in the literature describe great anatomic variations with regard to the atrioventricular connections, spatial relationships of the ventricles, and connections and spatial relationships of the great arteries. In the example described in this report, the basic anatomic picture was that of transposition of the great arteries, but the criss-cross atrioventricular valves had resulted in atrioventricular discordance; hemodynamically, therefore, the situation resembled congenitally corrected transposition. One hypothesis for this anatomic configuration is that pronounced counterclockwise rotation (as viewed from below) brought the ventricular septum into a frontal plane and altered the respective positions of the pulmonary and aortic valves from those usually seen in congenitally corrected transposition and thereby resulted in crossed atrioventricular connections. An alternative hypothesis is that in this case one of the atrioventricular valves (the anteriorly positioned valve) may represent an anomalous communication that developed early in embryogenesis and connected the left atrial appendage to the right ventricular infundibulum.