1. From the Departments of Medicine (Cardiovascular Division) (N.O., C.J.S., M.L.C., R.R.J., A.R.M., M.L., R.M.B., D.L., W.J.M.) and Radiology (W.J.M.), Beth Israel Deaconess Medical Center, Harvard Medical School, Boston; the Department of Mathematics and Statistics (P.G., S.J.B., M.G.L.), Boston University; and the National Heart, Lung, and Blood Institute’s Framingham Heart Study (P.G., D.L., M.G.L., C.J.O.), Framingham, Mass.