Department of Medicine, Division of Cardiology, University of Pittsburgh School of Medicine, UPMC Hypertrophic Cardiomyopathy Center, UPMC Heart and Vascular Institute, 200 Lothrop Street, Pittsburgh, PA 15213, USA. Electronic address: wongtc@upmc.edu. Division of Cardiology, Lehigh Valley Health Network, 1250 South Cedar Crest Boulevard, Suite 300, Allentown, PA 18103, USA.