**1. Introduction**

Following the initial description of the physiologically corrective operation for tricuspid atresia by Fontan and Baudet [1] and Kreutzer and his associates [2] almost simultaneously, such surgery was widely adapted by most pediatric cardiologists and pediatric cardiac surgeons. This concept of bypassing the right ventricle (RV) was further extended to manage other cardiac defects with a functionally single ventricle.

The original surgery as described by Fontan and Baudet [1] consisted of (1) end-to-end anastomosis of superior vena cava (SVC) with the right pulmonary artery (PA) (classical Glenn procedure [3]), (2) connection of the separated right PA to the right atrium (RA) either directly or through an aortic homograft, (3) closure of the defect in the atrial septum, (4) insertion of a pulmonary valve homograft into the orifice of the inferior vena cava (IVC), and (5) ligation of the main PA, to entirely bypass the RV. On the basis of the procedures performed, one must infer that Fontan's concept was to use the right atrium as a pumping chamber; therefore, he inserted a prosthetic valve into the IVC and right atrial-pulmonary artery junction.

On the contrary, Kreutzer et al. [2] anastomosed the right atrial appendage to the PA directly or by a pulmonary homograft and closed the ASD. Neither a Glenn procedure was performed nor a prosthetic valve was inserted in the IVC. Kreutzer's view appears to be that the RA does not function as a pump and that the left ventricle functions as a suction pump in the system.

The surgical procedure as generally performed appears to shadow Kreutzer's principle, and consequently, I have used the term "Fontan-Kreutzer operation" to describe this procedure [4–8]. However, because of priority of publication and more common usage in the literature, I will use the term "Fontan operation" in this chapter.

In this review, I will discuss the evolution of the Fontan concepts, the indications for Fontan operation, the Fontan procedure as used currently, and the results of old and current types of Fontan.
