The utility of hemodynamic ramp studies in single ventricle patients supported by continuous flow left ventricular assist devices (CF-LVADs) is largely unknown. We report the novel use of the hemodynamic ramp test to optimize a 26 year-old Fontan-palliated single-ventricle patient supported with a continuous-flow ventricular assist device (Heartware HVAD). Modest improvements in Fontan hemodynamics resulted in significant and persistent clinical improvement and symptomatic relief.