Angiography of atrioventricular canal defects.

The axial angiograms of 20 patients with an atrioventricular (A-V) canal defect were carefully examined and compared with anatomic observations made at operation. A common A-V valve was present in 15 patients and two separate valves in 5. The atrial septal defect, the anatomy of the ventricular septum and the morphology and functional status of the A-V valves were well demonstrated. There ws consistent angiographic deformation of the normally straight contour extending from the noncoronary aortic cusp to the crux cordis observed in the four chamber and elongated right anterior oblique projections of the left ventricular angiogram of each patient. This deformity is caused by the deficiency or absence of the A-V septum and is the best angiographic sign of the malformation. The differentiation of two separate valves from a common A-V valve was uniformly made. When a common A-V valve was present, three of the five leaflets were usually identified but distinction of the free floating from the tethered anterior leaflet was not always possible. It is concluded that axial techniques provide more complete angiographic definition of the anatomic abnormalities of A-V canal defects than are demonstrated from frontal and lateral views.