1. From the Departments of Physiology, Pediatrics, and Cardiothoracic Surgery (R.W.M., R.N.C., M.S., L.M.R., A.v.H., M.K., A.L., T.D., F.W.P.), Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands; Bakken Research Center (R.N.C.), Medtronic, BV, Maastricht, The Netherlands; and Medtronic, Inc (L.J.M., N.D.S.), Minneapolis, Minn.