[1] Harvard Univ, Sch Med, Vet Adm Hosp Boston, Div Cardiac Electrophysiol, West Roxbury, MA 02132 USA
[2] Harvard Univ, Sch Med, Massachusetts Gen Hosp, Ctr Human Genet Res, West Roxbury, MA 02132 USA
[3] Univ Minnesota, Sch Publ Hlth, Div Epidemiol & Community Hlth, Minneapolis, MN USA
[4] Univ Washington, Dept Biostat, Seattle, WA 98195 USA
[5] Vet Affairs Med Ctr, Div Cardiol, Minneapolis, MN USA
[6] Univ Minnesota, Med Ctr, Div Cardiol, Minneapolis, MN 55455 USA
[7] Univ Washington, Cardiovasc Hlth Res Unit, Seattle, WA USA
[8] Harvard Univ, Sch Med, Beth Israel Deaconess Med Ctr, Div Cardiol, West Roxbury, MA 02132 USA
[9] Beth Israel Deaconess Med Ctr, Div Gen Med & Primary Care Res, Boston, MA 02215 USA