Straddling atrioventricular valves in biventricular hearts. Observations made in 5 cases.

The report concerns 5 patients with straddling or overriding atrioventricular valves. The overriding phenomenon was found 4 times in tricuspid, once in mitral position. In addition to this malformation, 2 patients had congenitally corrected transposition of the great arteries (CTGA), one patient had transposition of the great arteries (TGA), and another a double outlet right ventricle (DORV). In 2 instances corrective surgery was done without compromising the anatomical and functional integrity of the straddling valve. Three patients with straddling degree B-C received palliative procedures, the ventricular septal defect (VSD) was left open in order to save the straddling atrioventricular valve and pulmonary artery banding was done for protection of the pulmonary vascularity. One corrected patient died in the early postoperative period.