1. Cardiomyopathy Unit, Careggi University Hospital, Florence, Italy (N.M., F.G., B.T., F.C., I.O.).
2. Erasmus Medical Center, Rotterdam, The Netherlands (M.M.).
3. Hypertrophic Cardiomyopathy Institute, Tufts Medical Center, Boston, MA (E.J.R., M.S.M., B.J.M.).
4. Royal Prince Alfred Hospital and Centenary Institute, University of Sydney, Australia (C.S.).