1. Cardiovascular Research Center (L.-C.W., O.L.H., P.T.E., S.A.L.)
2. Massachusetts General Hospital, Boston. Program in Medical and Population Genetics, The Broad Institute of Harvard and MIT, Cambridge, MA (L.-C.W., O.L.H., S.H.C., P.T.E., S.A.L.).
3. Department of Biostatistics, Boston University School of Public Health, MA (S.R.P., M.G.L., B.W., L.T., K.L.L.).
4. Boston University and National Heart, Lung and Blood Institute’s Framingham Heart Study, MA (S.R.P., M.G.L., L.T., L.S., H.L., K.L.L., E.J.B.).
5. Department of Medicine, Cardiology Division, University of Massachusetts Medical School, Worcester (D.D.M.).
6. Cardiovascular Research Center, Herlev and Gentofte University Hospital, Hellerup, Denmark (L.S.).
7. Department of Medicine, Sections of Computational Biomedicine (H.L.)
8. Cardiac Arrhythmia Service (P.T.E., S.A.L.)
9. Preventive Medicine and Cardiovascular Medicine (E.J.B.), Boston University School of Medicine, MA.