1. From the Hypertrophic Cardiomyopathy Center, Minneapolis Heart Institute Foundation, Minneapolis, Minn (B.J.M., A.K.A.), and the Hypertrophic Cardiomyopathy Center, Division of Cardiology, Tufts-New England Medical Center, Boston, Mass (N.A.M.E., M.S.M., M.S.L., J.E.U.).