Fontan operation.

D uring the past 4 decades, the Fontan operation has been carried out as a surgical treatment in patients with tricuspid atresia. Over the years, it has become established as a revolutionary therapy in patients with univentricular heart physiology. Many experimental and clinical studies have been performed with a view to understanding the Fontan circulation; in consequence, the operation has undergone several modifications and the prognosis of these patients has improved. However, Fontan circulation attrition still remains a problem; elevations in systemic venous pressure and pulmonary artery resistance, decreased preload and increased afterload, are factors that concern researchers in their efforts to improve the circulation. In this review, we focus on the problems of the operation and the questions arising from the study of Fontan circulation.