Disharmony between atrioventricular connections and segmental combinations: unusual variants of "crisscross" hearts.

Two congenitally malformed hearts are described, one studied in life and the other at autopsy, in which the topology of the ventricular mass was not as expected for the atrioventricular (AV) connection present. In Case 1, studied at autopsy, there was the usual atrial arrangement with a concordant AV connection. The morphologically right ventricle, however, was left-sided and the ventricular mass was of left-hand topology (l loop) rather than the expected right-hand pattern (d loop). In Case 2, studied during life, there was the usual atrial arrangement and a discordant AV connection. Rather than the anticipated left-hand topology (l loop), the ventricular mass was arranged in right-hand fashion (d loop) and the morphologically right ventricle was right-sided. The cases emphasize that for a full description of a congenitally malformed heart, it is often necessary to account for the topology of each segment as well as the connections (or alignment) among the segments.