EFIG 39.6 Virtual three-dimensional model of a double-outlet right ventricle with an atrioventricular septal defect and tetralogy-type interventricular communication Dark blue, atrioventricular valve annulus; purple, aortic valve annulus Double-outlet right ventricle is the most common indication for threedimensional printing in patients with congenital heart disease Threedimensional models allow for realistic appreciation of the surgical anatomy and facilitate surgical decision making and planning The heart can be printed in different ways, such as a solid surface model or as a hollow body, allowing for assessment of the intracardiac anatomy It is also possible to leave aspects of the cardiac cavities open to provide a better view of relevant intracardiac structures (Fig 39.28) This offers the opportunity to perform an intracardiac exploration prior to any surgical procedure (Videos 39.3 to 39.7) The surgical procedure can therefore be planned, permitting more precise estimation of the postoperative course and surgical risks Parents can be counseled more appropriately, and a better perspective can be given with regard to the expected postoperative course Most importantly, three-dimensional prints may play a crucial role in decision making regarding biventricular versus functionally univentricular repair when the decision is difficult Nonetheless, cases remain where an intraoperative intracardiac exploration changes the preoperative decision despite excellent imaging FIG 39.28 Three-dimensional printing of various forms of double-outlet right ventricle (A) Fallot-type double-outlet right ventricle with subaortic interventricular communication and pulmonary stenosis (B) Taussig-Bing anomaly with subpulmonary interventricular communication and aortic stenosis (C) Double-outlet right ventricle with doubly committed interventricular communication (D) Noncommitted remote interventricular communication Asterisk indicates interventricular communication Three-dimensional printing can be performed with various different materials, and the consistency of the model can be changed Printing of relatively soft and flexible models provides the opportunity to practice an intended procedure on the model itself Although such a mock procedure cannot give information on functional aspects of the repair, it provides better insight in the technical feasibility Three-dimensional printing remains limited with regard to valvar structures, especially the leaflets of the atrioventricular valves and the subvalvar apparatus Overriding and straddling may, for now, have to be finally assessed in the operating room