[1] Brigham & Womens Hosp, Heart & Vasc Ctr, 75 Francis St, Boston, MA 02115 USA
[2] Harvard Med Sch, 75 Francis St, Boston, MA 02115 USA
[3] Ronald Reagan UCLA Med Ctr, Ahmanson UCLA Cardiomyopathy Ctr, Los Angeles, CA USA
[4] Duke Univ, Sch Med, Duke Clin Res Inst, Durham, NC USA
[5] Univ Calgary, Dept Clin Neurosci, Calgary, AB, Canada
[6] Vet Affairs Palo Alto Hlth Care Syst, Palo Alto, CA USA
[7] Northwestern Univ, Dept Med, Div Cardiol, Feinberg Sch Med, Chicago, IL USA