In this study, a computational method is presented to simulate the hemodynamics of patients after the Fontan procedure. The short-term feedback control models are implemented to assess the hemodynamic responses of the patients exposed to stresses such as gravity or hemorrhage. To construct the base line state of the Fontan model, we assume an increase in venous tone, an increase in heart rate, and an increase in systemic resistance all of which are based on clinical observations. For the verification of the present method we simulate a lower body negative pressure (LBNP) test and hemorrhage (20% blood volume loss). Both simulation results are compared to experimental data from the literature. Furthermore, it is shown that cardiac output decreases when the shunt resistance increases.