[1] Virginia Commonwealth Univ, Richmond, VA USA
[2] Harvard Med Sch, Brigham & Womens Hosp, Heart & Vasc Ctr, Boston, MA USA
[3] Duke Univ, Sch Med, Dept Med, Durham, NC 27706 USA
[4] Duke Univ, Sch Med, Duke Clin Res Inst, Durham, NC USA
[5] VA Palo Alto Hlth Care Syst, Palo Alto, CA USA
[6] Northwestern Univ, Feinberg Sch Med, Div Cardiol, Chicago, IL 60611 USA
[7] Ronald Reagan UCLA Med Ctr, Ahmanson UCLA Cardiomyopathy Ctr, 0833 LeConte Ave,Room 47-123 CHS, Los Angeles, CA 90095 USA