1 Cardiovascular Disease Initiative, Broad Institute of MIT and Harvard, Cambridge, MA (D.P., P.T.E., S.K.).
2 Cardiovascular Research Center (D.P., G.F.M., P.T.E., S.K.).
3 Telemachus and Irene Demoulas Family Foundation Center for Cardiac Arrhythmias (D.P., G.F.M., P.T.E., S.K.), Massachusetts General Hospital, Boston, MA.
4 Department of Medicine (T.S.), Massachusetts General Hospital, Boston, MA.