Introduction and Hypothesis: Hypertrophic cardiomyopathy (HCM) phenotype itself is a slowly progressive disorder that manifests remarkable evolution of clinical features throughout life. End-stage phase of HCM characterized by left ventricular (LV) dilatation and systolic dysfunction shows a poor prognosis. Serum high-sensitivity cardiac troponin T (hs-cTnT) is considered to be a good marker for ongoing myocyte injury and this injury may be related to LV remodeling in HCM patients. However, there has been little information on clinical determinants associated with progression into end-stage HCM from HCM with preserved LV systolic function.Methods: We retrospectively studied 157 consecutive HCM patients (age: 59.9 ± 14.2 years, 197 men) who did not show end-stage HCM at initial evaluation of this study and performed serial echocardiography during the follow-up period of more than at least 1 year. End-stage phase of HCM was defined as LV systolic dysfunction of global ejection fraction < 50%.Results: Of 157 patients, 13 patients (8.3%) developed to end-stage HCM during follow-up period of 6.3 ± 2.8 years. Compared with patients who did not reach to end-stage HCM at last evaluation, patients with progression into end-stage phase showed larger LV size (p = 0.005), lower ejection fraction (p < 0.001), more enlarged left atrial diameter (p = 0.001), longer follow-up period (p = 0.039), and higher frequency of an elevated serum concentration of high-sensitivity cardiac troponin T (hs-cTnT: > 0.014 ng/ml) (p = 0.009) at registration. Multivariate analysis revealed that elevation of hs-cTnT value as well as lower ejection fraction was independently related to progression into end-stage phase of HCM.Conclusions: An elevated serum concentration of hs-cTnT was associated with progression of LV remodeling in patients with HCM and this biomarker can be useful to predict advancing to end-stage phase.