Introduction
Approximately 50 years ago, Francis Fontan pioneered an operation for tricuspid atresia that bears his name today.1 The Fontan procedure refers to any operation that shunts the systemic venous return to the pulmonary bed by bypassing the right ventricle (RV) or the subpulmonary ventricle. It can be applied to a wide array of congenital heart diseases such as tricuspid atresia, hypoplastic left heart syndrome and unbalanced atrioventricular canal where there is a single functional ventricle. Despite restoring normal oxygen levels in the body, the operation creates a neoportal system where adequate cardiac output can be generated only at the expense of increased systemic venous congestion.2 Additionally, the loss of pulsatility and chronic low-flow state of Fontan circulation induces pulmonary vasoconstriction and raises the pulmonary vascular resistance. This results in slow but relentless damage to the end organ systems, especially the liver. Numerous designs of assist devices that have been previously described provide a push to the venous blood entering the lungs to mimic a normal RV.3-5 A novel interventional approach in the form of an oscillating ball along the pulmonary artery pathway to improve the hemodynamics in failing Fontan circuit is studied herewith. The objective of the experimental study was to test the hypothesis that placement of an oscillating ball along the pulmonary artery pathway in an experimental Fontan model would increase the forward flow of blood into the lungs and reduce the pressure in the systemic veins.