We report three cases of corrected transposition (CT), all with Ebstein's disease, ventricular septal defect (VSD) and ventricular preexcitation. In cases 1 and 2, the ECG revealed sinus rhythm, with type A fusion preexcitation QRS complexes, suggesting left-sided Kent bundles and intact conduction system (CS). Complete serial section (SS) of the CS in both cases revealed an anterior CS and a Kent bundle in the posteroseptal wall of the morphologic right ventricle (MRV). Case 3 had intermittent preexcitation, with periods of complete atrioventricular (AV) block with narrow QRS escape rhythm. The preexcitation complexes suggested the presence of a left lateral Kent bundle. SS of the CS revealed a blind posterior and two anterior AV nodes, one on either side of the pulmonary trunk. The left anterior AV node was blind. The right anterior node formed the anterior bundle, which ended blindly. This bundle emerged again and joined a posterior bundle to form an interrupted sling around the closed VSD. In addition, there was a tenous Kent bundle at the posterolateral wall of the MRV. In summary: (1) preexcitation in CT with Ebstein's disease of the left AV valve is associated with Kent bundles; (2) fusion complexes reflected intact CS; and (3) intermittent preexcitation with AV block was associated with the presence of tenuous Kent bundl and discontinuity of the CS.

A thick band of muscular tissue interposed between the posterior aortic wall and the anterior leaflet of the mitral valve could be indentified on M-mode sweeps of 3 patients with double outlet right ventricle. A discrete subaortic crista supraventricularis, continuous with the anterior wall of the right ventricle, could also be identified. These signs are specific for double outlet right ventricle and are not present in other anomalies of the heart.