Background: The study objective was to test underlying physical laws behind a proposed novel device for failing Fontan and investigate whether the device could be implemented theoretically to improve hemodynamics in failing Fontan circulation. Methods: A 4-arm setup was designed and fabricated to simulate an actual Fontan circuit in the form of a junction of the superior and inferior vena cavae (SVC, IVC) with the right and left pulmonary arteries (RPA, LPA). A provision for placement of an oscillating ball along the RPA-LPA path to push fluid away from SVC and IVC was created. The rate of ball oscillations and initial pressure of fluid on SVC and IVC limbs were varied. The pressure-drop times in the vena cavae limbs were measured at varying ball oscillations and resistances in the RPA-LPA pathway. The test was considered positive if increasing oscillations of the ball allowed for quicker pressure drop in the SVC and IVC limbs indicating quicker discharge of fluid through the RPA and LPA. 48 different experiments were conducted to simulate different physical conditions and the results were plotted and analyzed to draw a conclusion. Results: The time required for pressure drop in the experiment without ball was the least across all set of readings. This meant that placing an oscillating ball along the RPA -LPA path created obstruction to flow rather than enhance it. Increasing rate of ball oscillations increased degree of obstruction to flow. Conclusion: The proposed interventional method is unsuitable for improving hemodynamics in failing Fontan circulation.

We report a case of a 17-year-old healthy male presenting with multisystem hyperinflammatory shock temporally associated with COVID-19. Cardiac involvement was suspected based on evidence of significant cardiac injury (elevated cardiac biomarkers, electrocardiographic and echocardiographic abnormalities). Cardiac magnetic resonance imaging was performed demonstrating global biventricular systolic dysfunction, as well as a small area of T2 hyperintensity and mid wall late gadolinium enhancement. This case discusses the varied cardiac involvement in pediatric patients with COVID-19 infection and highlights that cardiac injury is not just limited to hyperinflammatory syndrome related global dysfunction but a more focal myocarditis can also be seen.