Interrelationship of LV mass, focal fibrosis by LGE, and diffuse fibrosis by T1-changes in patients with hypertrophic cardiomyopathy

Background Hypertrophic cardiomyopathy (HCM) is characterised by left ventricular hypertrophy, myofibre disarray as well as interstitial and replacement fibrosis. These characteristics are likely the underlying cause of reduced ventricular compliance and cardiac arrhythmias which subsequently impact on quality of life and outcome. Cardiac magnetic resonance (CMR) based late gadolinium imaging (LGE) has emerged as a prognosticator in multiple cardiac myopathies, including HCM, and is able to demonstrate a type of myocardial scarring that has been likened to replacement fibrosis. CMR based T1 mapping techniques on the other hand are thought to be able to also detect a more diffuse increase in collagen volume fraction of myocardial tissue (i.e. diffuse fibrosis). It has been argued that the latter type of fibrosis may be reversible up to a certain stage. However, even in the physiologically unlikely scenario that both fibrotic processes were independent of each other above mentioned CMR based technologies are not.