Atrioventricular septal defect: quantitative anatomy of the left ventricle.

A morphometric study was performed in 18 human hearts with atrioventricular septal defect not associated with other anomalies; 16 hearts had common atrioventricular orifices, and 2 presented separate right and left atrioventricular orifices. A total of eight parameters were analyzed, characterizing ventricular wall thickness, length and circumference of the inflow and outflow tracts, and circumference of the left orifice and aortic orifice. The data were compared with previously published patterns of normality. In addition, the volume of the aortic outflow tract was calculated. The inflow tract was shorter than the outflow tract, and the length of the diaphragmatic wall was equal to the sum of the lengths of the inflow tract and ventricular wall thickness at the level of the apex.