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
It has previously been described that normal, healthy subjects have decreased exercise
performance in a supine vs upright position. However, due to high venous pressures and the
need for systemic venous return to overcome gravity in order to perfuse the lungs, one might
hypothesize that Fontan patients would have increased exercise performance in a supine vs
upright position. The investigators are interested in studying this hypothesis.
- S/p Fontan palliation > 2 years prior
- Age 8 to 30 years
- Pacemaker dependence
- Severe hypoxemia (O2 saturation <80%)
- Recent atrial flutter or other arrhythmias
- Protein losing enteropathy (PLE)
- Severe atrioventricular valve regurgitation
- History of cardiac arrest
- Significant comorbidities (renal failure, asthma, etc).