From The Danish National Research Foundation Centre for Cardiac Arrhythmia (I.E.C., L.S.R., S.H., J.H.S.), Department of Cardiology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark; the Danish Twin Register, Institute of Public Health (A.S., K.C.), University of Southern Denmark, Odense, Denmark; Department of Biostatistics (E.B.-J.), University of Copenhagen, Copenhagen, Denmark; and the Department of Surgery and Medicine (S.H., H.S.), Faculty of Health Sciences, University of... (2009-08時点)