Superior vena caval obstruction in total anomalous pulmonary venous connexion.

Total anomalous pulmonary venous connexion may be conveniently classified into supradiaphragmatic and infradiaphragmatic types (Smith, Frye, and Newton, I96I). Infradiaphragmatic forms are usually associated with obstruction to pulmonary venous flow (Johnson et al., I958) and the supradiaphragmatic types are said only rarely to have pulmonary venous obstruction (Lucas et al., I963). However, obstruction to pulmonary blood flow has been described in the latter type and lately increasing attention has been given to this factor. The purpose of this report is to document an unusual type of obstruction to pulmonary venous blood flow in a case of supradiaphragmatic total anomalous pulmonary venous connexion. The possible embryological origin of this defect and the types of obstruction seen in the supradiaphragmatic form will also be discussed.