[1] Duke Clin Res Inst, Durham, NC USA
[2] Duke Univ, Sch Med, Durham, NC USA
[3] Univ Calif Los Angeles, Ahmanson UCLA Cardiomyopathy Ctr, Los Angeles, CA USA
[4] Northwestern Univ, Feinberg Sch Med, Chicago, IL 60611 USA
[5] Vet Affairs Palo Alto Hlth Care Syst, Palo Alto, CA USA
[6] Stanford Univ, Stanford, CA 94305 USA
[7] Brigham & Womens Hosp, Boston, MA 02115 USA
[8] Harvard Univ, Sch Med, Boston, MA USA