The purpose of this study is to non-invasively characterize the fibrotic consequences of
single ventricle physiology, its possible solution and effect on lymphatics. This project
investigates the response to acute imposition of Fontan hemodynamics by examining the
interrelationship between liver and cardiac fibrosis/dysfunction and lymphatic congestion
along with a pilot trial of the antifibrotic agent, spironolactone, to prevent these
consequences and to determine if MRI can discern these differences. The combination of serum
biomarkers and MRI form a powerful non-invasive tool in putting together this complicated web
of dysfunction.