Cardiorespiratory responses to exercise after the Fontan operation.

O riginally described for the treatment of tricuspid atresia, the concept of ventricular exclusion and direction of systemic venous blood from the right atrium immediately into the pulmonary artery has been applied to a variety of forms of single ventricle. Theoretically, this operation should eliminate the right-to-left shunt and decrease the volume of systemic ventricular blood flow. Fontan's original description included a Glenn anastomosis, incorporation of a valve into the right atrium to pulmonary arterial connection, and insertion of a valve into the inferior vena caval-right atrial junction. There have been numerous modifications of the original operation. Many investigators think that a prior Glenn anastomosis is unnecessary and that insertion of valves into the inferior vena caval-right atrial junction and right atriumpulmonary artery connection are unnecessary. The