1. From the Department of Experimental Cardiology, Heart Failure Research Center (J.M.T.d.B.), Amsterdam, The Netherlands; the Departments of Cardiology (F.H.M.W.) and Medical Physiology (J.M.T.d.B.), University Medical Center, Utrecht, The Netherlands; and the Interuniversity Cardiology Institute of the Netherlands (J.M.T.d.B.), Utrecht, The Netherlands.