1. Cardiology Division (A.R., P.T.E., M.E.L.), Massachusetts General Hospital, Boston.
2. Cardiovascular Research Center (A.R., P.T.E., M.E.L), Massachusetts General Hospital, Boston.
3. Cardiovascular Disease Initiative, Broad Institute, Cambridge, MA (A.R., P.T.E., M.E.L.).
4. Harvard Medical School, Boston, MA (A.R., P.T.E., M.E.L.).
5. Division of Cardiology, University of California San Francisco (J.P.P.).