We aimed to investigate the interaction between systolic myocardial and intraventricular kinetic energy (KEmyo, KEven) in Fontan patients. The tissue phase mapping and 4D flow datasets were acquired for calculation of KEmyo and KEven. The Fontan group showed decreased peak and mean systolic KEven, and decreased peak and mean systolic KEmyo. The KE delay, describing the subtraction of time-to-peak KEmyo from time-to-peak KEven, in Fontan group significantly correlated with peak and mean systolic KEven. In conclusion, the correlation between KE delay and KEven illustrated the adverse impact of abnormal energy transferring mechanism on the single functional ventricle in Fontan patients.