From NeuroSearch A/S (J.G.D., L.S., U.S.S., M.G.), Ballerup, Denmark; Danish National Research Foundation Center for Cardiac Arrhythmia (J.G.D., T.J., M.G.), Panum Institute, University of Copenhagen, Copenhagen, Denmark; Department of Clinical Biochemistry (E.D.B.), University Hospital of Copenhagen, Rigshospitalet, Copenhagen, Denmark; Zealand Pharma A/S (R.S.H.), Glostrup, Denmark. (At 2011-06)