Complications associated with heterotaxy syndrome in Fontan patients.

Enormous progress has been made in the last decade toward decreasing the risk of the Fontan operation and optimizing early and intermediate outcomes. Heterotaxy syndrome patients, with their extensive constellation of anatomic abnormalities, constitute a challenging group to manage surgically. Palliative procedures early in life are directed at creation of a satisfactory balance between pulmonary and systemic blood flow and at the same time assurance of unobstructed pulmonary venous return. For heterotaxy patients who survive beyond the newborn period, and are considered to have nonseptatable hearts, early reduction of the volume load of the functional single ventricle is extremely important. Early conversion from parallel pulmonary and systemic circulations to a superior cavopulmonary anastomosis (bidirectional Glenn or hemi-Fontan) is the preferred strategy. Traditionally, those patients with heterotaxy who survive initial surgical management have been considered a very high-risk population with respect to an eventual Fontan procedure. In heterotaxy patients it is particularly important to understand the unique and variable anatomy of the sinus node and conduction system, the potential for occult pulmonary venous obstruction, the tendency for development of atrioventricular valve regurgitation in volume loaded ventricles, and the potential for recurrent or persistent cyanosis because of intrahepatic shunting or pulmonary arteriovenous malformations.