BACKGROUND: Although small elevations of high-sensitive cardiac troponin T (hs-cTnT) are associated with incident heart failure (HF) in the general population, the underlying mechanisms are not well defined. Evaluating the association of hs-cTnT with replacement fibrosis and progression of structural heart disease before symptoms is fundamental to understanding the potential of this biomarker in a HF prevention strategy. METHODS: We measured hs-cTnT at baseline among 4986 participants in MESA (Multi-Ethnic Study of Atherosclerosis), a cohort initially free of overt cardiovascular disease (CVD). Cardiac magnetic resonance imaging was performed at baseline. Repeat cardiac magnetic resonance was performed 10 years later among 2831 participants who remained free of interim CVD events; of these, 1723 received gadolinium-enhanced cardiac magnetic resonance for characterization of replacement fibrosis by late gadolinium enhancement. Progression of subclinical CVD was defined by 10-year change in left ventricular structure and function. Associations of hs-cTnT with incident HF, CV-related mortality, and coronary heart disease were estimated using Cox regression models. RESULTS: Late gadolinium enhancement for replacement fibrosis was detectable in 6.3% participants without interim CVD events by follow-up cardiac magnetic resonance. A graded association was observed between higher baseline hs-cTnT categories and late gadolinium enhancement (>= 7.42 ng/L versus <limit of detection [12% (highest category versus= 8.81 ng/L versus <limit of detection; adjusted hazards ratio, 5.59; 95% CI, 2.97-10.68). CONCLUSIONS: hs-cTnT levels are associated with replacement fibrosis and progressive changes in left ventricular structure in CVD-free adults, findings that may precede HF symptoms by years. Minor elevations of hs-cTnT may represent a biochemical signature of early subclinical cardiac disease, providing an opportunity for targeted preventive interventions.