Cardiomyopathy Hypertrophic cardiomyopathy SNOMEDCT_US:45227007 HCM UMLS:C0007194 Cardiomyopathy, hypertrophic Enlarged and thickened heart muscle SNOMEDCT_US:233873004 HP:0001639 Hypertrophic cardiomyopathy (HCM) is defined by the presence of increased ventricular wall thickness or mass in the absence of loading conditions (hypertension, valve disease) sufficient to cause the observed abnormality.