1. From the Department of Physiology (E.E.V., A.C.G.v.G., J.B., L.N.B.), the Department of Anatomy and Embryology (A.W., M.W.M.M., J.L.M.V., W.H.L.), and the Department of Clinical and Experimental Cardiology (J.M.T.d.B., T.O.), Academic Medical Center, University of Amsterdam, The Netherlands.