 Fontan-palliated patients comprise an interesting group of single-ventricle patients who are dependent upon passive return of blood from the body to the lungs. Systemic venous pressures are therefore quite elevated, and one study demonstrated that venous capacitance was diminished. In addition, these patients have markedly diminished aerobic capacity Max VO2. Although one recent study demonstrated that Fontan patients can increase their Max VO2 through diligent cardiac rehabilitation, their ultimate results were still well below average. 