1. From the National Heart, Lung and Blood Institute's Framingham Heart Study, Framingham, MA (J.W.M., M.F.S., J.D., E.J.B.); Section of Cardiovascular Medicine, Department of Medicine, Boston University, Boston, MA (J.W.M., H.L., E.J.B.); Department of Cardiology, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands (M.R.); Cardiovascular Research Center (M.F.S., S.A.L., P.T.E.) and Cardiac Arrhythmia Service (S.A.L., P.T.E.), Massachusetts General Hospital, Boston;...