A study of 31 dogs, divided into two groups, was conducted to compare direct atrioventricular with atriopulmonary connection using a valved conduit to treat tricuspid atresia. The first group (n= 9) acted as controls. In the second group (n = 22), an experimental model was established for direct atrioventricular connection that could be converted to atriopulmonary connection. In subgroup A (n = 11), the blood from the right atrium (RA) was conducted to a haemodynamically effective residual right ventricle (RV), whereas in subgroup B (n = 11) the blood was conducted from the RA to an ineffective residual RV. There were haemodynamic advantages of atrioventricular connection in subgroup A. No such differences were found between the two surgical techniques in subgroup B. In both subgroups, light external compression of the pulmonary artery produced a profound deterioration in the haemodynamic state. The technique of direct atrioventricular connection does not appear to offer any advantages as a method of atriopulmonary bypass.
