1. From the Departments of Biomedical Engineering/Biophysics (E.H., A.P.G.H., K.D.R.), Cardiology (M.H.M.W., J.L.W.), Physiology (R.S.R.), and Internal Medicine (A.A.K.), Cardiovascular Research Institute Maastricht/Maastricht University Medical Centre, Maastricht, The Netherlands.